Change all your settings to optimize your PC for max power usage. Turn your windows power settings to max perf. And go into your nvidia control panel and make sure its on max perf too.

You might have the windows game bar DVR thing enabled, so that could be why some things are lagging when you try to record with OBS.

Check your clock speeds and temps when you are at 100% Could be thermal throttling.

Did you change your power settings make sure you haven’t limited your CPU max speed.

When at 100% look at your programs that are running, what is taking up your CPU power.

Back up your shit to multiple places.

You can get something like Plex and it can help you organize it in different ways, rather than trying to organize via folders.

Ideally, get a raid setup going, and then back that up to one large drive.

Raid is a bit risky, cause you need the same drives, and all of them will have similar wear patterns, so it is possible that all drives die around the same time.(though rare). So having that one extra offline copy is good.

Contact the authorities and maybe the FBI.

What your roommate did is highly illegal.

I would assume your computer is entirely compromised now, and you are not going to be able to remove what he did unless you do a system restore, or completely reinstall windows.

Get a burner phone. Use that when you go out. Keep your locked phone in your dorm.