Hi Gustav,
If I had to guess, you’re probably on the right track here. It’s likely the high resolution and two screens is overloading your memory and causing Unreal to fallback to traditional shadow maps. A few debug commands you can try to test this theory:
r.Shadow.Virtual.Debug 1 to confirm the Shadow Maps are indeed not running
r.ScreenPercentage 50 to see if lowering the screen resolution reenables VSM
Scalability to see if any settings are being automatically downgraded by your hardware
stat gpu to see if your gpu is running out of memory
If any of these raise flags, we can go from there!