If you like the interface of the steam deck in desktop mode and you are most familiar with Ubuntu, you could try Kubuntu… which is just Ubuntu with the KDE desktop environment like what the deck has. Theres also the KDE Fedora spin. If you do want to go the Arch route you could install EndeavourOS, which is practically arch with a little bit of hand holding to get you on your feet quickly - and to help you learn the ropes.