You were broken up. She was within every rights.
And even if she weren't, in your eyes, she did what every one of us does in this situation : attempt to change your mind off a difficult time. Some of us work themselves to death, other drown in alcohol, many turn to religion while one can also try to engage in physical contact, all just to fill a void.
It was a hookup. It happens. Now if you think she is "soiled" because of this, or whatever you seem to imply, look inside of you and find out what's reaaly bothering you.
If you can't forgive her for something she was in every right to do, then just move on and stop the wound from oozing pus and making both of you bitter.
And that's personal but... grow up. Your life does not need to end where it began. Move elsewhere, even if the project remains the same. Fond some compromise or you're gonna lose her again.
It's very good - in some cases better than Windows. I have a MSI gaming laptop. The battery lifedin longer on linux compared to Windows.
With custom scripts you can control fan speed. However... I have a intel/nVidia card on KDE with wayland and it is hell. Nothing works as expected, so I can't tell about gaming in itself.
For other tasks, it works really well.