IINA - Video player that is much better than Mac’s built in one. HIGHLY Recommend this one, it’s an amazing player

AppCleaner - A much better way to uninstall apps of MacOS, removes config files, and files that would be left behind normally under a typical install. It’s a portable app, so it’s not really “installed” on the system.
LinearMouse - fixes acceleration stuff for 3rd party mice, scrolling speed and acceleration, lets you have scrolling be independent of trackpad scroll direction if you prefer Natural Scrolling, etc.
RunCat - Not necessary, but just fun to have. The cat runs faster the harder your mac is working. Also makes it nice to check quickly your ram usage, cpu utilization, etc.

MonitorControl - App to control the brightness of 3rd party monitors

You’d have to replace the screen to fix that. Your other option is just using it with an external monitor, either closed, or could do what some people online do and make it a headless macbook. If you wanted to try to sell it for parts down the road though I wouldn’t recommend the latter

https://www.reddit.com/r/mac/comments/10z7lpw/want_to_clear_other_users_storage/

Can give some of these solutions a try. I’d try checking hidden directories in Library, if that doesn’t work, I’m not sure. Best of luck