The problem is Paradox's launcher. The solution is to circumvent it.
This is one way to do that:
Now on to the reason I'm here; I'm finding the performance is just plain awful. Even on the lowest settings, it's still putting my graphics card at 70°C. Does anybody have any ideas on how to improve it?
proton 7.0-1bx1 2022-03
Compatibility Report
System Information
I confirm:
steam-684450.log
Symptoms
Runs but nothing happens for a while, then stops again.
Reproduction
Click play.