Most regular distros are good enough for gaming. The only issue you’re likely to run into is with graphics drivers (I recommend going for AMD graphics on that build), and the availability of certain software in certain formats (gaming software is more likely to be available for Debian or Ubuntu based distros).
If you like the Steam Deck’s desktop mode, you might enjoy another distro with the same desktop environment (KDE Plasma). I’m partial to KDE Neon, a snappy Ubuntu LTS spin with all of the latest KDE software.