I've been exclusively using Silverblue (well, Kinoite, which is the KDE version) as my main workstation OS for at least 8 months, and gaming on it is no different from other operating systems. Once you install Steam from Flathub, it all just works. The only difference is that you might need to give Steam permission to access your external drives if you want to add a Steam library on them. KDE Plasma lets you do it from the system settings app easily.

For generic Wine usage, I just use Lutris. Steam does allow you to add non-Steam games and run them through Proton, but IMO Lutris' interface is easier for doing more advanced Wine stuff without having to drop into a terminal. That's personal preference though.

As far as drivers, I didn't have trouble installing the Nvidia driver (I have a 1080 TI). I don't remember exactly what I did to install it system wide, since that was many months ago, but it was easy and well-documented IIRC.

What's more complicated is getting the driver to work in graphical apps launched from toolboxes. If you're doing development, or expect to build graphical software/games from source, you'll likely need to deal with this. Basically, you just need to install the driver again inside of the toolbox, and make sure it's the same version as what's installed on your base system. I have some scripts to automate this if you're interested, but it's not really that useful unless you're planning to use toolboxes a lot.

Overall, I'm very happy with Silverblue/Kinoite. The immutable base system gives me a lot of confidence on the long-term reliability of the system. Originally, I expected it to be a real blocker for most software, but the only thing I couldn't get working was TeamViewer (didn't try that hard tho tbh). I've even been able to get complex stuff to work like Unity, O3DE, Stable Diffusion webui, and a bunch of other AI-related stuff that is normally hard to install even on a regular system.

Fedora Kinoite: 9/10 -- highly recommend