If you copied over your home user folder there may be some permission issues in the hidden directories where apps store their settings. If you suspect anything in your user directory might be an issue test creating and logging in with a new user account and see if everything works there.

Sounds like a permission problem from migrating files over, run steam from terminal to see precise errors.

We even have an app for it now: apt install hollywood

Yeah, thankfully those tend not to be the titles I have any interest in playing. Just more high budget over marketed repetitive DLC and DRM ridden shiny piles of garbage. </rant>

My guess would be to play games smoothly that are so horribly un-optimized they run poorly on all hardware.

Games got a lot more complicated and many use so many 3rd party add-ins that just sorting through what you have rights to release can be a pretty big task and not worth it if what you can release ends up unusable with all of them removed.