Re: LOW FPS with RTX 3080 Asus Strix
I had this exact same issue with my 3080 FE. In DX12 mode the game was essentially UNPLAYABLE (20ish FPS, around 8 FPS in campaign) unless it was all in low. Once DX12 was disabled everything ran great at 60 FPS
This was also running with an AMD 5950X, did you happen to be running on an Intel or AMD CPU?
The weird part is the game ran great with DX12 enabled 1080TI and Intel i7 4770K, so it's weird the 3080 would struggle.