I have a lot of respect for Canonical for driving a distro that was very "noob friendly" in an ecosystem where that's genuinely hard.
But I mostly agree with you. Once you get out of that phase, I don't really see much value in Ubuntu. I'd pick pretty much anything else for everything I do these days. Debian/Fedora/Alpine on the server. Arch on the desktop.
I have been running Linux for a long time as well (I used Mandrake linux) and I find Ubuntu mostly nice. What I would not say is that it is not stable or useful. The long LTS cadences give it much time to be very stable and you can also be more on the edge when you use the in between versions.
So I'd say it is very much a personal preference but just saying it is not stable is just not generally true. I could say the same about Fedora that shipped graphics drivers so new that all my software was broken for a while. To each their own I guess.
Ubuntu has never ever been the most stable or useful distro. What it did have was apt and more up to date stuff than debian.
I would never willingly choose Ubuntu if allowed other options (Fedora, Debian, maybe CoreOS, etc)