I can't comment on specifics. I'm back in linux after several years away in mac land. The snap experience is awful, and confusing. I have not had the same experience with flatpaks. They seem to act more like regular apps that you update. The issue with snap is that firefox will say the snap needs to update, and that the update is pending warning my I only have days (or hours) to use it, but no way to actually do the upgrade. Then it will say its upgrading, but nothing happens. I just keep using firefox, and every once in a while it may say something like the update failed (I honestly can't remember, since I just ignore any notification with the word 'snap' in it since they're all meaningless). Eventually, when I quit firefox, it might update and quit pestering me. But how knows? Maybe it won't upgrade, and then I'll open it again and it won't be upgraded.

Flatpaks, I can just update in the package GUI (Discover for me, since KDE) alongside other updates, and we roll on.

Distro-wise, I dunno :/ I like ubuntu cause its more standardized in terms of software availability

most things will support an ubuntu package. However, I'm really considering just jumping into debian and going with the rolling releases.