I’ve been on Silverblue (well, Kinoite) for quite a while now, and the only issue I remember having was that I had to use flatseal once to give steam access to an external drive when adding a new library folder.

Everything seems to work fine. I’ve never been prevented from playing a game when I wanted to due to immutability or flatpak issues.

Bazzite is silver blue plus steam. Works decently well

All my games work the same as a non inmutable distro. Steam, Lutris, Heroic, Bottles, Retroarch, all those apps are on flathub, so ive never felt limited in that regard.

An annoyance i had with steam flatpak is when you configure multiple locations for installing games on the same drive. Steam will just show them all as "/var/cache/" no matter what youve actually set them to.

From what ive read, Steam flatpak is not an option for you. Bazzite is a variant of Silverblue but it has set up an arch container with the latest version of steam. They did this bc they considered it to use too many undesirable workarounds. Maybe that could work for you.

Flatpak has it largely covered at this point, especially with most DE's stores supporting their update prompts. Come to NixOs and meet the misses

SteamVR in Flatpak functions but you will get rediced performance because it can't set CAP_SYS_NICE for vrcompositor. I haven't checked if setting it manually could work though

I have a HTPC setup for steam gaming using Micro OS. I haven’t touched it in a few months, but for the earlier parts of this year I frequently played Dead Cells, Art of Rally, Bloodstained, Vampire Survivor, Stardew Valley, games like that.

I used a couple of PS4 controllers via Bluetooth, just using the touchpad on the controller for if I needed to use a mouse cursor on the desktop or something.

One gripe was that I couldn’t get MicroOS to auto login, so I had to keep a keyboard next to the tv so I could sign in everything I wanted to play a game.

ive been using the steam flatpack on silverblue for a while now.

there are a few cases where steam wont start (less then once every 2 months i think)
that usually are resolved by updating the flatpack.

otherwise i have not noticed any other issues.

https://boilingsteam.com/how-i-built-my-new-linux-gaming-desktop-in-2021-with-amd-cpugpu-and-gnu-guix/

There's this article about gaming on Guix which I found very interesting but difficult to replicate. Guix is still quite difficult to set up in my opinion, but probably awesome once you get everything working.