If you want to install any apps go with Flatpaks for reliability. Since Ubuntu has snaps, install the snap variant of available. Imo Flatpaks have greatly reduced the number of issues like dependency problems for me.
Have you tried any other distro ? I'd recommend any of the universal blue projects or fedora silverblue as it is relatively maintainance free and just like using windows/macos. If you game just go with Bazzite, otherwise try Aurora/Bluefin. In most cases you won't even have to use the terminal that much, but if you do they have really nice cli tools too.
If you still want to go the traditional approach - Arch based distros can also be very good, ateast you will be able to find answers on the archwiki and try those solutions. It's not like Ubuntu is bad, it's kind of janky sometimes and I kind of liked the conveince of finding all that I need within the archwiki. Arch has fast updates, so things will break once in a while.. however my experience has been really good with arch for many years now. if you want to try it then go with either EmdavourOS or CachyOS - both are setup quite well out of the box.
TL;DR - try Flatpaks, try low maintenance distros like Bazzite and use it like you normally do.
The old galaxies were really good. I remember s3 being the first experience with a flagship device.. it felt really advanced for the time. It sucks that now samsung has implemented knox security or whatever to detect bootloader unlocked devices. That's the reason why I switched to a Oneplus phone and gave my last samsung to my dad.
I also remember touchwiz being an absolute lag fest, back in the day. Cyanogen was the OG savior !