Can you recommend me other (non atomic) distros that play nice with both secure boot and nvidia drivers?

I wouldn’t exactly recommend it because of the learning curve, but I have the exact setup you’re looking for working on NixOS.

Lanzaboote made it pretty easy. The downside is that you need to put secure boot into user-managed mode, and some asshole anticheats might not like that even though only Microsoft-signed executables were used in the boot chain of Windows.