I removed bluetooth support from the laptop on April 10 2023, and WLAN provided by the Mediatek 7921 chip has been working flawlessly since then for, at the time of writing, 28 days, with numerous suspends and resumes.
To me this strongly indicates that using bluetooth was the problem, especially since it seems to be provided by the Mediatek 7921 chip as well. Note that I'm also running the Mx Master mouse, using the provided USB plug instead of using bluetooth. That also works flawlessly. (Nevertheless: I have other bluetooth devices so it would be nice to get bluetooth on this laptop, that doesn't make WiFi stop working) I removed bluetooth support by removing all packages with "blue" in their name, with the exception of libbluetooth3 (I initially uninstalled that as well, but that pulled out network-manager as well, so I had to put it back in). These are the packages I "apt remove"'d: apt remove bluez bluez-obexd gnome gnome-bluetooth gnome-core pulseaudio-module-bluetooth task-gnome-desktop \ qml-module-org-kde-bluezqt:amd64 libkf5bluezqt6:amd64 libkf5bluezqt-data libgnome-bluetooth13:amd64 gir1.2-gnomebluetooth-1.0:amd64
