16 days ago - AndrewT - Direct link
What antivirus app do you use? Make sure the new eu4.exe is in all its exceptions lists.

What happens if you unload GeForce Experience entirely before starting the game?

And what happens if you run eu4.exe by itself, no Steam?  
16 days ago - AndrewT - Direct link
I have see GFE make our games run worse before, which is how I knew to suggest that step.