Would I rather have the deb package be up-to-date? Sure. But when I've used distributions that try to stick closer to the bleeding edge everywhere, I've had bad experiences with stuff breaking. This lets me keep a stable, well-tested distribution for everything except for the one package I want to be newer.
I can't compare to Flatpak or AppImage because I've never used them.
I really wonder how i can have such a different experience to theirs apart from really esoteric parts/apps. Not saying it's not happening.
While i'd prefer just using apt, they let me work without being a pain so i don't really care.
Is there another option for that than Snap, or Docker which is a bit too complicated to set up? (that’s not rhetorical, I would like to know if there is)
I think the argument over flat pack versus snaps may expressed in technological terms but in reality, it's just your damn ego. Let it go, it's really not worth arguing over. Use what solves your work problem and then go have a life away from computers.
It's really not. First, those technical problems are real problems that will create user-visible problems, ex. forced updates. Second, it has problems that are already user-facing, ex. startup times.