Hi, there! Most people here probably use Pop!_OS so this isn’t required, but if you use System76 tools (like the scheduler and power daemons) on recent Gnome versions, then you may want to take a look at this fork.
I’ve made this because I use System76 tools with ArchLinux that has a newer Gnome version that isn’t supported by the stock Gnome extension. Maybe it’s useful to someone else.
Cheers
Does it work in the login screen?
Have you followed the instructions that can be found in the official support pages to install Plasma? Installing a different DE in Pop (or any other distro that comes with a DE preinstalled) isn’t so simple. You may want to test if the problem persists if you login with a brand new user, if not then it means that something in ~/.config is probably broken.