you’re on the right track, i think, but not bazzite–that carries a lot of extra stuff that isn’t necessary here. just ordinary fedora silverblue. clean up the app grid or put dash-to-dock on it and put the few launchers they need down on that. gnome is actually a good desktop for basic users that just need to run one or a few applications. updates are somewhat frequent but should be almost entirely automatic.

i have a few users like your parents on endless os, which is similar to silverblue, just based on an in-house immutable debian instead of silverblue’s fedora base. i rarely ever hear from them, it ‘just works’. i also have it at home, it’s currently my only linux desktop there (i do most my ‘work’ at the office, home is just doom-scrolling and media for the most part these days). updates are less frequent but endless is switching to a gnome os base with the next major version. that will probably increase the frequency of updates a bit compared to their older debian base. that upgrade to v7 should be mostly invisible to the user, they’ve done a good job in the past with upgrades.