Ubuntu continuously updates itself without permission, killing apps and losing previous stateI've never seen this happen and I've run Ubuntu in production for years. Apt does not auto-update unless it's configured for unattended upgrades — and both Debian and Ubuntu allow you to configure unattended upgrades in apt. And unattended upgrades via apt should not kill running user processes or cause data loss.
The Ubuntu packages, drivers, and kennel are laughably behind Debian.
This is just plain wrong — even for the steelman argument of Debian unstable or testing, which are not intended for general use. Debian unstable and testing are on kernel 6.12. Ubuntu 25.04 is on kernel 6.14.
Debian stable, meanwhile, is on 6.1. Ubuntu has the far more-recent kernel.
I don't know what you mean by "drivers" — there aren't separate drivers on Linux from the kernel; they're shipped in the kernel. Ubuntu's are also more recent than Debian, since the kernel version is more recent.
With respect to packages, obviously I can't check every package version, but e.g. coreutils in Ubuntu are on 9.5, released in March 2024; systemd on Ubuntu is a version released this year (and until last month Debian unstable and Ubuntu were identical); gcc is identical; etc. While Ubuntu occasionally lags Debian unstable, it's not by much.
If you compare to actual Debian stable, it's not even close. Debian stable is ancient.
And ultimately... Why are you using Debian unstable? It's called "unstable" for a reason. It receives basically no testing. Even the "testing" version is more stable, and that's not intended to be stable at all and doesn't necessarily receive security updates. Ubuntu is less-stable than Debian stable, but far more up-to-date; Debian testing is less-stable than Ubuntu... And usually still not even as up-to-date. Debian unstable is basically untested; if you want that you'd be better served by a rolling release distro like Arch where the packages are going to be way more up-to-date anyway.
The Debian wiki cautions against treating unstable or testing releases as general purpose, so I truly don't think even this steelman is viable. [1] In fact, they refuse to even call Debian unstable a "release" since there are no release practices associated with it and the code is effectively untested.
Ubuntu is nowhere near my favorite Linux distro, but claiming it's more out of date than Debian is just FUD.
Debian is very very stable — at least, Debian stable is — and people love it for that. But the tradeoff is that everything in it is ancient. If you want something that's like Debian, but more up-to-date but slightly less stable — that's Ubuntu. If you want a rolling release, that's Arch. (And of course, there are even more-different distros like NixOS or ostree-based ones; there's the Red Hat universe of RHEL and the closer-to-bleeding-edge Fedora; etc etc.) Using Debian unstable is either a magnanimous act of sacrifice in order to help test future Debian versions, or it's self-harm.
Personally if I wanted to use a Debian-derivative on the desktop, though, I'd probably use System76's PopOS, which is basically a cleaned-up Ubuntu with some nice GNOME extensions. I'm more curious in the future to try out ostree-based distros, though, like the various Fedora Atomic ones, since they have nice rollbacks without the user-facing complexity of NixOS.
1: https://wiki.debian.org/DebianUnstable