When I start KDE neon, I get only a black screen. Earlier everything was mostly working as it should, and I'm not really sure what changed that broke it. I can get into a terminal with ctrl+alt+F5, but I have no clue what I could do to find out what could be the problem, or how to resolve it. I tried updating all packages to the latest versions, but that didn't help.

[UPDATE] I found out that the login-screen is there, it is just black. So I managed to log in and run programs in windows. However, the desktop and menu don't work, and instead the background is just black. I also noticed that while most programs still work, both Firefox and Brave don't work. At some point a got a screen asking me to report the crash of the main menu, but I coundn't install the necessary packages for generating the usefull information about the crash.