Hey there @tea-hot! Welcome back to the community!
This references a graphics DLL most of the time, and since it’s functioning in 5.0.3 and not in 5.1.1 it’s safe to assume this may be an issue between the GPU drivers and DX12/Sm6.6.
Since you’d already swapped down to studio drivers, I don’t have to reference that they are regularly more stable. You’d also already reset the GPU settings, and cleared the cache so that’s good.
A couple questions/things to try:
Quick double check the drivers are up to date.
What Anti-Aliasing are you using for the project? Try swapping that around in the Project Settings (or just setting it to none) and seeing how everything runs.
Does swapping down to DX11 relieve it? (This can help verify the issue and also be a temporary workaround)
One user that had a particularly resistant issue like this solved it:
Another batch of possible workarounds/solutions from a previous thread: