diff --git a/src/app/cmdoptions.cpp b/src/app/cmdoptions.cpp
index 0b993c3a6..45f9cee6f 100644
--- a/src/app/cmdoptions.cpp
+++ b/src/app/cmdoptions.cpp
@@ -134,11 +134,6 @@ namespace
         }
     };
 
-    bool operator==(const QString &arg, const BoolOption &option)
-    {
-        return (option == arg);
-    }
-
     // Option with string value. May not have a shortcut
     struct StringOption : protected Option
     {
@@ -181,11 +176,6 @@ namespace
         }
     };
 
-    bool operator==(const QString &arg, const StringOption &option)
-    {
-        return (option == arg);
-    }
-
     // Option with integer value. May not have a shortcut
     class IntOption : protected StringOption
     {
@@ -233,11 +223,6 @@ namespace
         }
     };
 
-    bool operator==(const QString &arg, const IntOption &option)
-    {
-        return (option == arg);
-    }
-
     // Option that is explicitly set to true or false, and whose value is undefined when unspecified.
     // May not have a shortcut.
     class TriStateBoolOption : protected Option
@@ -316,11 +301,6 @@ namespace
         bool m_defaultValue;
     };
 
-    bool operator==(const QString &arg, const TriStateBoolOption &option)
-    {
-        return (option == arg);
-    }
-
     constexpr const BoolOption SHOW_HELP_OPTION {"help", 'h'};
     constexpr const BoolOption SHOW_VERSION_OPTION {"version", 'v'};
 #if defined(DISABLE_GUI) && !defined(Q_OS_WIN)
diff --git a/src/base/bittorrent/infohash.cpp b/src/base/bittorrent/infohash.cpp
index 1a6035353..9558c4209 100644
--- a/src/base/bittorrent/infohash.cpp
+++ b/src/base/bittorrent/infohash.cpp
@@ -120,8 +120,3 @@ bool BitTorrent::operator==(const BitTorrent::InfoHash &left, const BitTorrent::
 {
     return (static_cast<InfoHash::WrappedType>(left) == static_cast<InfoHash::WrappedType>(right));
 }
-
-bool BitTorrent::operator!=(const BitTorrent::InfoHash &left, const BitTorrent::InfoHash &right)
-{
-    return !(left == right);
-}
diff --git a/src/base/bittorrent/infohash.h b/src/base/bittorrent/infohash.h
index fa033d0ae..fbf6b8f95 100644
--- a/src/base/bittorrent/infohash.h
+++ b/src/base/bittorrent/infohash.h
@@ -90,7 +90,6 @@ namespace BitTorrent
     std::size_t qHash(const TorrentID &key, std::size_t seed = 0);
 
     bool operator==(const InfoHash &left, const InfoHash &right);
-    bool operator!=(const InfoHash &left, const InfoHash &right);
 }
 
 Q_DECLARE_METATYPE(BitTorrent::TorrentID)
diff --git a/src/base/bittorrent/sessionimpl.cpp b/src/base/bittorrent/sessionimpl.cpp
index 4500b11f9..1c5930260 100644
--- a/src/base/bittorrent/sessionimpl.cpp
+++ b/src/base/bittorrent/sessionimpl.cpp
@@ -1571,37 +1571,48 @@ void SessionImpl::initMetrics()
         return index;
     };
 
-    // TODO: switch to "designated initializers" in C++20
-    m_metricIndices.net.hasIncomingConnections = findMetricIndex("net.has_incoming_connections");
-    m_metricIndices.net.sentPayloadBytes = findMetricIndex("net.sent_payload_bytes");
-    m_metricIndices.net.recvPayloadBytes = findMetricIndex("net.recv_payload_bytes");
-    m_metricIndices.net.sentBytes = findMetricIndex("net.sent_bytes");
-    m_metricIndices.net.recvBytes = findMetricIndex("net.recv_bytes");
-    m_metricIndices.net.sentIPOverheadBytes = findMetricIndex("net.sent_ip_overhead_bytes");
-    m_metricIndices.net.recvIPOverheadBytes = findMetricIndex("net.recv_ip_overhead_bytes");
-    m_metricIndices.net.sentTrackerBytes = findMetricIndex("net.sent_tracker_bytes");
-    m_metricIndices.net.recvTrackerBytes = findMetricIndex("net.recv_tracker_bytes");
-    m_metricIndices.net.recvRedundantBytes = findMetricIndex("net.recv_redundant_bytes");
-    m_metricIndices.net.recvFailedBytes = findMetricIndex("net.recv_failed_bytes");
-
-    m_metricIndices.peer.numPeersConnected = findMetricIndex("peer.num_peers_connected");
-    m_metricIndices.peer.numPeersDownDisk = findMetricIndex("peer.num_peers_down_disk");
-    m_metricIndices.peer.numPeersUpDisk = findMetricIndex("peer.num_peers_up_disk");
-
-    m_metricIndices.dht.dhtBytesIn = findMetricIndex("dht.dht_bytes_in");
-    m_metricIndices.dht.dhtBytesOut = findMetricIndex("dht.dht_bytes_out");
-    m_metricIndices.dht.dhtNodes = findMetricIndex("dht.dht_nodes");
-
-    m_metricIndices.disk.diskBlocksInUse = findMetricIndex("disk.disk_blocks_in_use");
-    m_metricIndices.disk.numBlocksRead = findMetricIndex("disk.num_blocks_read");
+    m_metricIndices =
+    {
+        .net =
+        {
+            .hasIncomingConnections = findMetricIndex("net.has_incoming_connections"),
+            .sentPayloadBytes = findMetricIndex("net.sent_payload_bytes"),
+            .recvPayloadBytes = findMetricIndex("net.recv_payload_bytes"),
+            .sentBytes = findMetricIndex("net.sent_bytes"),
+            .recvBytes = findMetricIndex("net.recv_bytes"),
+            .sentIPOverheadBytes = findMetricIndex("net.sent_ip_overhead_bytes"),
+            .recvIPOverheadBytes = findMetricIndex("net.recv_ip_overhead_bytes"),
+            .sentTrackerBytes = findMetricIndex("net.sent_tracker_bytes"),
+            .recvTrackerBytes = findMetricIndex("net.recv_tracker_bytes"),
+            .recvRedundantBytes = findMetricIndex("net.recv_redundant_bytes"),
+            .recvFailedBytes = findMetricIndex("net.recv_failed_bytes")
+        },
+        .peer =
+        {
+            .numPeersConnected = findMetricIndex("peer.num_peers_connected"),
+            .numPeersUpDisk = findMetricIndex("peer.num_peers_up_disk"),
+            .numPeersDownDisk = findMetricIndex("peer.num_peers_down_disk")
+        },
+        .dht =
+        {
+            .dhtBytesIn = findMetricIndex("dht.dht_bytes_in"),
+            .dhtBytesOut = findMetricIndex("dht.dht_bytes_out"),
+            .dhtNodes = findMetricIndex("dht.dht_nodes")
+        },
+        .disk =
+        {
+            .diskBlocksInUse = findMetricIndex("disk.disk_blocks_in_use"),
+            .numBlocksRead = findMetricIndex("disk.num_blocks_read"),
 #ifndef QBT_USES_LIBTORRENT2
-    m_metricIndices.disk.numBlocksCacheHits = findMetricIndex("disk.num_blocks_cache_hits");
+            .numBlocksCacheHits = findMetricIndex("disk.num_blocks_cache_hits"),
 #endif
-    m_metricIndices.disk.writeJobs = findMetricIndex("disk.num_write_ops");
-    m_metricIndices.disk.readJobs = findMetricIndex("disk.num_read_ops");
-    m_metricIndices.disk.hashJobs = findMetricIndex("disk.num_blocks_hashed");
-    m_metricIndices.disk.queuedDiskJobs = findMetricIndex("disk.queued_disk_jobs");
-    m_metricIndices.disk.diskJobTime = findMetricIndex("disk.disk_job_time");
+            .writeJobs = findMetricIndex("disk.num_write_ops"),
+            .readJobs = findMetricIndex("disk.num_read_ops"),
+            .hashJobs = findMetricIndex("disk.num_blocks_hashed"),
+            .queuedDiskJobs = findMetricIndex("disk.queued_disk_jobs"),
+            .diskJobTime = findMetricIndex("disk.disk_job_time")
+        }
+    };
 }
 
 lt::settings_pack SessionImpl::loadLTSettings() const
diff --git a/src/base/bittorrent/torrentimpl.cpp b/src/base/bittorrent/torrentimpl.cpp
index 8ecd1e98a..6fb3e72bd 100644
--- a/src/base/bittorrent/torrentimpl.cpp
+++ b/src/base/bittorrent/torrentimpl.cpp
@@ -31,7 +31,6 @@
 
 #include <algorithm>
 #include <memory>
-#include <type_traits>
 
 #include <libtorrent/address.hpp>
 #include <libtorrent/alert_types.hpp>
@@ -551,8 +550,7 @@ QVector<TrackerEntry> TorrentImpl::trackers() const
 
 void TorrentImpl::addTrackers(QVector<TrackerEntry> trackers)
 {
-    // TODO: use std::erase_if() in C++20
-    trackers.erase(std::remove_if(trackers.begin(), trackers.end(), [](const TrackerEntry &entry) { return entry.url.isEmpty(); }), trackers.end());
+    trackers.removeIf([](const TrackerEntry &entry) { return entry.url.isEmpty(); });
 
     const auto newTrackers = QSet<TrackerEntry>(trackers.cbegin(), trackers.cend())
             - QSet<TrackerEntry>(m_trackerEntries.cbegin(), m_trackerEntries.cend());
@@ -596,8 +594,7 @@ void TorrentImpl::removeTrackers(const QStringList &trackers)
 
 void TorrentImpl::replaceTrackers(QVector<TrackerEntry> trackers)
 {
-    // TODO: use std::erase_if() in C++20
-    trackers.erase(std::remove_if(trackers.begin(), trackers.end(), [](const TrackerEntry &entry) { return entry.url.isEmpty(); }), trackers.end());
+    trackers.removeIf([](const TrackerEntry &entry) { return entry.url.isEmpty(); });
     std::sort(trackers.begin(), trackers.end()
         , [](const TrackerEntry &lhs, const TrackerEntry &rhs) { return lhs.tier < rhs.tier; });
 
diff --git a/src/base/bittorrent/tracker.cpp b/src/base/bittorrent/tracker.cpp
index eb6f5606b..6da1321cd 100644
--- a/src/base/bittorrent/tracker.cpp
+++ b/src/base/bittorrent/tracker.cpp
@@ -135,11 +135,6 @@ namespace BitTorrent
         return (left.uniqueID() == right.uniqueID());
     }
 
-    bool operator!=(const Peer &left, const Peer &right)
-    {
-        return !(left == right);
-    }
-
     std::size_t qHash(const Peer &key, const std::size_t seed)
     {
         return qHash(key.uniqueID(), seed);
diff --git a/src/base/bittorrent/tracker.h b/src/base/bittorrent/tracker.h
index 6a54ca3a9..892c5f3e2 100644
--- a/src/base/bittorrent/tracker.h
+++ b/src/base/bittorrent/tracker.h
@@ -64,7 +64,6 @@ namespace BitTorrent
     };
 
     bool operator==(const Peer &left, const Peer &right);
-    bool operator!=(const Peer &left, const Peer &right);
     std::size_t qHash(const Peer &key, std::size_t seed = 0);
 
     // *Basic* Bittorrent tracker implementation
diff --git a/src/base/digest32.h b/src/base/digest32.h
index 11c0c314b..5fdace840 100644
--- a/src/base/digest32.h
+++ b/src/base/digest32.h
@@ -144,12 +144,6 @@ bool operator==(const Digest32<N> &left, const Digest32<N> &right)
             == static_cast<typename Digest32<N>::UnderlyingType>(right));
 }
 
-template <int N>
-bool operator!=(const Digest32<N> &left, const Digest32<N> &right)
-{
-    return !(left == right);
-}
-
 template <int N>
 bool operator<(const Digest32<N> &left, const Digest32<N> &right)
 {
diff --git a/src/base/indexrange.h b/src/base/indexrange.h
index 65129f5ea..37931f791 100644
--- a/src/base/indexrange.h
+++ b/src/base/indexrange.h
@@ -107,11 +107,6 @@ public:
             return (*left == *right);
         }
 
-        friend constexpr bool operator!=(const Iterator &left, const Iterator &right)
-        {
-            return !(left == right);
-        }
-
     private:
         IndexType m_index;
     };
diff --git a/src/base/net/downloadmanager.cpp b/src/base/net/downloadmanager.cpp
index 55192ec60..6a955f26b 100644
--- a/src/base/net/downloadmanager.cpp
+++ b/src/base/net/downloadmanager.cpp
@@ -42,7 +42,6 @@
 #include <QSslError>
 #include <QUrl>
 
-#include "base/algorithm.h"
 #include "base/global.h"
 #include "base/logger.h"
 #include "base/preferences.h"
@@ -63,7 +62,7 @@ public:
     {
         const QDateTime now = QDateTime::currentDateTime();
         QList<QNetworkCookie> cookies = Preferences::instance()->getNetworkCookies();
-        Algorithm::removeIf(cookies, [&now](const QNetworkCookie &cookie)
+        cookies.removeIf([&now](const QNetworkCookie &cookie)
         {
             return cookie.isSessionCookie() || (cookie.expirationDate() <= now);
         });
@@ -75,7 +74,7 @@ public:
     {
         const QDateTime now = QDateTime::currentDateTime();
         QList<QNetworkCookie> cookies = allCookies();
-        Algorithm::removeIf(cookies, [&now](const QNetworkCookie &cookie)
+        cookies.removeIf([&now](const QNetworkCookie &cookie)
         {
             return cookie.isSessionCookie() || (cookie.expirationDate() <= now);
         });
@@ -90,7 +89,7 @@ public:
     {
         const QDateTime now = QDateTime::currentDateTime();
         QList<QNetworkCookie> cookies = QNetworkCookieJar::cookiesForUrl(url);
-        Algorithm::removeIf(cookies, [&now](const QNetworkCookie &cookie)
+        cookies.removeIf([&now](const QNetworkCookie &cookie)
         {
             return !cookie.isSessionCookie() && (cookie.expirationDate() <= now);
         });
@@ -102,7 +101,7 @@ public:
     {
         const QDateTime now = QDateTime::currentDateTime();
         QList<QNetworkCookie> cookies = cookieList;
-        Algorithm::removeIf(cookies, [&now](const QNetworkCookie &cookie)
+        cookies.removeIf([&now](const QNetworkCookie &cookie)
         {
             return !cookie.isSessionCookie() && (cookie.expirationDate() <= now);
         });
diff --git a/src/base/net/proxyconfigurationmanager.cpp b/src/base/net/proxyconfigurationmanager.cpp
index 00bc7cedd..4494280d4 100644
--- a/src/base/net/proxyconfigurationmanager.cpp
+++ b/src/base/net/proxyconfigurationmanager.cpp
@@ -41,11 +41,6 @@ bool Net::operator==(const ProxyConfiguration &left, const ProxyConfiguration &r
             && (left.hostnameLookupEnabled == right.hostnameLookupEnabled);
 }
 
-bool Net::operator!=(const ProxyConfiguration &left, const ProxyConfiguration &right)
-{
-    return !(left == right);
-}
-
 using namespace Net;
 
 ProxyConfigurationManager *ProxyConfigurationManager::m_instance = nullptr;
diff --git a/src/base/net/proxyconfigurationmanager.h b/src/base/net/proxyconfigurationmanager.h
index 5444fb193..41521823d 100644
--- a/src/base/net/proxyconfigurationmanager.h
+++ b/src/base/net/proxyconfigurationmanager.h
@@ -57,7 +57,6 @@ namespace Net
         bool hostnameLookupEnabled = true;
     };
     bool operator==(const ProxyConfiguration &left, const ProxyConfiguration &right);
-    bool operator!=(const ProxyConfiguration &left, const ProxyConfiguration &right);
 
     class ProxyConfigurationManager final : public QObject
     {
diff --git a/src/base/path.cpp b/src/base/path.cpp
index 75bf074ed..2ed951773 100644
--- a/src/base/path.cpp
+++ b/src/base/path.cpp
@@ -342,11 +342,6 @@ bool operator==(const Path &lhs, const Path &rhs)
     return (lhs.data().compare(rhs.data(), CASE_SENSITIVITY) == 0);
 }
 
-bool operator!=(const Path &lhs, const Path &rhs)
-{
-    return !(lhs == rhs);
-}
-
 Path operator/(const Path &lhs, const Path &rhs)
 {
     if (rhs.isEmpty())
diff --git a/src/base/path.h b/src/base/path.h
index 16bf51f71..4501e2668 100644
--- a/src/base/path.h
+++ b/src/base/path.h
@@ -95,7 +95,6 @@ private:
 Q_DECLARE_METATYPE(Path)
 
 bool operator==(const Path &lhs, const Path &rhs);
-bool operator!=(const Path &lhs, const Path &rhs);
 Path operator+(const Path &lhs, QStringView rhs);
 
 QDataStream &operator<<(QDataStream &out, const Path &path);
diff --git a/src/base/preferences.cpp b/src/base/preferences.cpp
index fe5addf6e..809826faa 100644
--- a/src/base/preferences.cpp
+++ b/src/base/preferences.cpp
@@ -702,7 +702,7 @@ QVector<Utils::Net::Subnet> Preferences::getWebUiAuthSubnetWhitelist() const
 
 void Preferences::setWebUiAuthSubnetWhitelist(QStringList subnets)
 {
-    Algorithm::removeIf(subnets, [](const QString &subnet)
+    subnets.removeIf([](const QString &subnet)
     {
         return !Utils::Net::parseSubnet(subnet.trimmed()).has_value();
     });
diff --git a/src/base/rss/rss_autodownloadrule.cpp b/src/base/rss/rss_autodownloadrule.cpp
index 8caff1037..b4637cf43 100644
--- a/src/base/rss/rss_autodownloadrule.cpp
+++ b/src/base/rss/rss_autodownloadrule.cpp
@@ -167,11 +167,6 @@ namespace RSS
         return (left.m_dataPtr == right.m_dataPtr) // optimization
                 || (*(left.m_dataPtr) == *(right.m_dataPtr));
     }
-
-    bool operator!=(const AutoDownloadRule &left, const AutoDownloadRule &right)
-    {
-        return !(left == right);
-    }
 }
 
 using namespace RSS;
diff --git a/src/base/rss/rss_autodownloadrule.h b/src/base/rss/rss_autodownloadrule.h
index 9e5449bc6..ff54b5faf 100644
--- a/src/base/rss/rss_autodownloadrule.h
+++ b/src/base/rss/rss_autodownloadrule.h
@@ -108,6 +108,4 @@ namespace RSS
 
         QSharedDataPointer<AutoDownloadRuleData> m_dataPtr;
     };
-
-    bool operator!=(const AutoDownloadRule &left, const AutoDownloadRule &right);
 }
diff --git a/src/base/utils/version.h b/src/base/utils/version.h
index 98bff202f..ba2618a7b 100644
--- a/src/base/utils/version.h
+++ b/src/base/utils/version.h
@@ -124,13 +124,12 @@ namespace Utils
             return res;
         }
 
-        // TODO: remove manually defined operators and use compiler generated `operator<=>()` in C++20
-        friend bool operator==(const ThisType &left, const ThisType &right)
+        friend constexpr bool operator==(const ThisType &left, const ThisType &right)
         {
             return (left.m_components == right.m_components);
         }
 
-        friend bool operator<(const ThisType &left, const ThisType &right)
+        friend constexpr bool operator<(const ThisType &left, const ThisType &right)
         {
             return (left.m_components < right.m_components);
         }
@@ -159,12 +158,6 @@ namespace Utils
         std::array<int, N> m_components {{}};
     };
 
-    template <int N, int Mandatory>
-    constexpr bool operator!=(const Version<N, Mandatory> &left, const Version<N, Mandatory> &right)
-    {
-        return !(left == right);
-    }
-
     template <int N, int Mandatory>
     constexpr bool operator>(const Version<N, Mandatory> &left, const Version<N, Mandatory> &right)
     {
diff --git a/src/gui/properties/peerlistwidget.cpp b/src/gui/properties/peerlistwidget.cpp
index afae06d64..9f6b37b08 100644
--- a/src/gui/properties/peerlistwidget.cpp
+++ b/src/gui/properties/peerlistwidget.cpp
@@ -67,12 +67,9 @@ struct PeerEndpoint
 {
     BitTorrent::PeerAddress address;
     QString connectionType; // matches return type of `PeerInfo::connectionType()`
-};
 
-bool operator==(const PeerEndpoint &left, const PeerEndpoint &right)
-{
-    return (left.address == right.address) && (left.connectionType == right.connectionType);
-}
+    friend bool operator==(const PeerEndpoint &left, const PeerEndpoint &right) = default;
+};
 
 std::size_t qHash(const PeerEndpoint &peerEndpoint, const std::size_t seed = 0)
 {