I had the same problem and managed to fix it a few minutes ago.
I’ll list the steps I took in order to do it:
- Reinstalled UE4 v4.25.4
- Reinstalled NVIDIA Studio Driver v461.40
- Inside NVIDIA Control Panel, under Manage 3D Settings, in Preferred graphics processor, set to High-performance NVIDIA processor.
- In WindowsUpdates, check for updates and install them all (this is what actually fixed it for me).
Hope this helps!