Comment 60 for bug 1834085

Disabling upower isn't enough -- it will start up again when an app (such as your browser) requires power management support. You have to uinstall upower from your system. (Note that this will make some apps, such as steam, unstable.)

This bug started happening when I switched out my wifi card. I have a Dell XPS 9560. My Magic Mouse only started having these disconnect issues after I switched to an Intell 9260 card. I might switch back to Killer card to verify.

I caught upower doing its (bad) thing just now, after being started up by brave browser.

Apr 26 22:21:21 nodoubt dbus-daemon[833]: [system] Activating via systemd: service name='org.freedesktop.UPower' unit='upower.service' requested by ':1.2664' (uid=1000 pid=15830 comm="/usr/lib/brave/brave ")
Apr 26 22:21:21 nodoubt systemd[1]: Starting Daemon for power management...
Apr 26 22:21:23 nodoubt dbus-daemon[833]: [system] Successfully activated service 'org.freedesktop.UPower'
Apr 26 22:21:23 nodoubt systemd[1]: Started Daemon for power management.
Apr 26 22:26:14 nodoubt bluetoothd[831]: Can't get HIDP connection info
Apr 26 22:26:15 nodoubt kernel: magicmouse 0005:05AC:030D.000D: unknown main item tag 0x0

Magic mouse is now disconnected.

If I completely uninstall upower, the problem goes away.