Unreal 4 games won't load when using DX12

Whenever I try and load an Unreal game (The Bus, Train Sim World 2 etc) using DX12 the game won’t start and I get a crash.

If I revert back to DX11 it works fine. I have other games running using DX12 (such as Red Dead Redemption 2) so I don’t think it is a Card/DX12 issue.

I also downloaded the Unreal engine in EPIC, and added -DX12 to the end and this also causes a crash (works fine without the -DX12)

I am running an i9 11900k and a 3080 card. 32 GB of DDR4 (quite a fast rig).

Could anyone possibly point me into the right direction of what to try.

I did try uploading the UE crash log, but I am not allowed to upload