I'm trying to avoid a re-install, but I might have no choice.
Began this install with Solus 4.1 MATE to give it a shot after using Budgie since the beginning. Installed Budgie alongside using the documentation about Desktop Environments. Decided I did in fact like Budgie better, and removed the MATE packages to leave Budgie.
I now note that certain Control Center applets don't work normally, namely the Mouse & Touchpad one.
Attached is a screenshot from my install:
Attached is a screenshot from Budgie Live:
In practice, this means I can't customize any of my Mouse & Touchpad settings, and tap-to-click does not work, which is not fun.
I've tried usysconf -f all, reinstalling gnome-settings-daemon, etc.