Is there something I am supposed to do on a Wacom Cintiq to turn on pressure sensitivity in Krita? I added Krita in the Wacom app, but the brushes still have no pressure sensitivity.

I googled around trying to find a fix but it just ended in breaking Krita entirely lol so I had to reinstall it.

If you're on Windows or macOS, you need to install the drivers for the Cintiq. If you have done that, and there is no pressure in Krita, then the drivers are not properly installed or the driver settings file is broken. There is no configuration need in Krita whatsoever.

This is true for all brands of tabets: if there are problems with pressure sensitivity, it's a driver problem. It is never, ever, no matter what happens in other applications, a Krita problem.