10 years ago I would've agreed that Ubuntu is the most reliable option.

For me now it comes across as a bit clunky, unpolished and less coherent compared to Fedora Silverblue — Ubuntu has more visible seams where it's been built from separate projects.

A major upgrade of Silverblue is literally 3 clicks plus the time it takes to do a normal restart. It doesn't ask questions a non-techy doesn't care about, and they can't break it.

(I'm not saying your choice of Ubuntu is “wrong” or anything, but if you haven't yet done so, it's worth installing a previous version of Silverblue and role-playing how it would work for a non-techy audience long-term.)