The functionality is already there and sure, it could be made more user-friendly. But that requires a lot of invested time and money, which can be pretty lacking in the open source space. If the Linux developers had Microsoft resources then Windows would be long dead.

Maybe try a better distro if you can’t confuigure the one you use? I haven’t had problems on Arch after setting it up properly.

Since when is Linux = Gnome?

If you want to install up to date packages and make your own environment inside SteamOS you need to use Distrobox. It comes pre-installed.

balenaEtcher never worked for me. No image that I flashed has been usable to boot. The RPi imager has been working flawlessly

The Steam controller 2 will be releasing soon if you want trackpads and extra buttons. I also think Valve is licencing to third parties. IIRC 8bitdo will make a Steam Controller