scriptsafe VS CachyOS-Browser-Settings

If there is a keylogger or virus on your laptop then your #1 priority should be to get rid of it. From the information you've given here, it's impossible to tell what it is or how hard it might be to remove. Someone (trustworthy!) with physical access to the computer might have a better chance at figuring that out. But honestly, the best way to be sure is to reinstall the operating system from scratch. (Yes, you will lose any files that aren't backed up, but that's kind of the point, you have to get rid of everything associated with the keylogger.) Once that's done, you should see if you can prevent yourself from getting another one. Again, it's hard to know what you should actually be doing without knowing how the presumed keylogger got on your computer in the first place, but as a start it might help to install some browser extensions which can help websites from running sketchy code - I personally use uBlock Origin and Script Safe (or NoScript is a fine alternative to the latter), and Ghostery is another one a lot of people like.

usually trial and error. On desktop I use scriptsafe which is a whitelister, so you start with everything blocked and work your way to figure out what you want.

uBlock usually handles all of them on youtube for me, but I also run scriptsafe on my browser.

This issue is tracked by Brave here and here. It looks like it's a low priority, but ScriptSafe might help; "prevent system fonts from being enumerated through elements."