1- Sometimes the file manager just won’t open and I get the error “Could not register nemo as a remote: Timeout was reached” when running it through the command line
2- Steam doesn’t work most of the time, games won’t launch, downloads won’t pause and I can’t exit out of steam, however, I can still navigate around the app.
Has anyone else ran into these issues and how are they solved?
Have you tried disabling GPU hardware acceleration for Steam? It sounds like steam is rendering poorly - I had a problem with blacked out pages with steam with nvidia and found it resolved been I turned off GPU acceleration. This was a while ago though - I’m not having issues on latest drivers and have GPU acceleration back up.
Here is a guide on how to turn it on/off within steam itself. https://thegeekpage.com/how-to-enable-disable-gpu-accelerated-rendering-in-steam/ Note this is purely for the steam client, it has no impact on games or proton etc. The intro on the linked page seemingly misunderstands the settings it then talks about!
In terms of Nemo, I’ve not had that issue myself; on searching I can see random different solutions to the problem so it doesn’t seem simple to resolve. Although frustrating you could switch to a different file manager. Thunar isn’t bad and works well with cinnamon. PcMan-fm also isn’t bad. There is little difference from Nemo with either. You can find both easily in the software store, or in Synaptic or in a terminal via searching with apt. Once insralled you can then change the default file manager in the cinnamon settings.
My favourite is Dolphin but I use KDE rather than Cinnamon. You might not want to mix KDE and Cinnamon apps? (It’ll work fine, but they do have different design philosophies and aesthetics, and may be jarring when compared to other file dialogues within other apps).