I don't understand how for some people it "never works", while for me it's literally never once failed, all the way from 6.10 up until now, my latest desktop install lasting through 12 updates, plus motherboard and GPU change (between Intel and AMD CPU, and Nvidia and AMD proprietary driver and then AMD open source driver no less) and four different desktop environments (Unity, Gnome, Mate, and finally KDE).
The closest it's ever come to failing was literally yesterday when I realized that my desktop was still on 19.04 and they had closed the old repositories so the GUI upgrade utility failed. The CLI upgrade didn't skip a beat, though.
Do you run mysql / MariaDB? That's the one that bites me, 100% of the time. There are other packages that often require "adjustments" but the db makes dist-upgrade a total fail for me.
The closest it's ever come to failing was literally yesterday when I realized that my desktop was still on 19.04 and they had closed the old repositories so the GUI upgrade utility failed. The CLI upgrade didn't skip a beat, though.