The author experienced severe latency spikes on their desktop computer, affecting gaming and audio/video calls. They initially suspected a damaged USB port but found that the issue persisted on a new computer. Various troubleshooting attempts failed until they discovered that using MediBang Paint Pro was causing the spikes. Further investigation revealed that Qt5 applications checking for wifi changes every 10 seconds caused the problem. Setting the environment variable QT_BEARER_POLL_TIMEOUT to -1 fixed the issue. The author expressed surprise at Qt5 being the unexpected cause of their system-wide wifi problems. Influential sources: https://invent.kde.org/graphics/krita/-/commit/d4eaaa63af8dc769acf79cd497e741f1de9be31b, https://github.com/sqlitebrowser/sqlitebrowser/issues/1209, https://github.com/mumble-voip/mumble/issues/1585, https://community.amd.com/thread/209327, https://github.com/Mudlet/Mudlet/issues/1587, https://github.com/MultiMC/MultiMC5/issues/1422, https://lostdomain.org/2017/06/17/qt-qnetworkaccessmanager-causing-latency-spikes-on-wifi/
https://ryuuta.net/blog/diagnosing-an-unsual-wifi-issue/