May be less Nobara and more KDE. I love KDE but 6 defaults to Wayland and that is not a good mix with Nvidia in my experience. I am on OpenSuSE Tumbleweed on my main gaming desktop and had numerous problems at the beginning of the year when KDE 6 launched but since switching to X11 have had no issues. I have tried Wayland a couple of times since KDE updates and it has improved but remains flaky in my view. On a separate home media PC I use Nobara with an integrated AMD GPU I've not had any issues with KDE and Wayland.

When it comes to immutable desktops, I like the idea but be aware they do have their downsides. Installing custom software relies on universal formats like Flatpak (which have their own overhead and downsides, and not all of the packages are "official") and if what you want is not available then it can be a pain having to use virtualisation and containers for a less locked down system, especially if dependencies for software are complex. They can bloat quickly but storage is dirt cheap these days so might not matter to you. I still find it too much faff. These are not insurmountable and may be worth it if concerned about the security and stability benefits. For me that's particularly problematic as I like to try out niche programmes and play with the latest versions of emulation tools. If you like to tinker then immutable can get in the way.

I must admit though, I am someone who is (generally) quite happy to reinstall if I break the system. However the purported stability and security of immutable systems does make sense if you want a good system that "just works".

Overall, in my experiences with Nobara and separately KDE and Nvidia have been good, as long as you avoid Wayland. May be worth a relook if the immutable nature of Bazzite isn't for you.

Edit: should say I did consider Nobara for my desktop PC but opted to try OpenSuSE first. I really like it and haven't had issues setting it up for gaming so I've not bothered switching. But Nobara in my media PC in my living room has been super convenient as it "just works" when it comes to controllers and all the gaming set up, so I also haven't bothered switching that to OpenSuSE. Both are good.

Yeah, Nvidia is pretty bad on Linux in general in my experience. Especially with Wayland. AMD and Wayland run very well, however.