Ubuntu packages get updated on a much faster cadence then Debian in my experience.
In my experience, the stability concerns are overblown, and it makes for a really nice rolling release system. I've had individual systems run for over a decade on a Debian testing install with rolling updates, and it's generally been far less of a headache than Ubuntu releases.
Edit: I just checked for the classic case of latest Python (3.11), and the answer for Debian is to build from source, which is annoying (not difficult to compile, but then future updates can't be pulled in via apt). Does Debian not have a vibrant PPA community to fill the gaps like Ubuntu?
Yeah, it does: the Ubuntu PPA community. (See https://wiki.debian.org/CreatePackageFromPPA, and similar.)
Nowadays you can get a full featured, well integrated and properly working user land on Linux with next to zero customisation with systemd and Gnome. I really recommend using a distribution which stays as close to vanilla as possible.
Debian would still patch far too much to my taste without the integration anyway.
They remove/rebrand what they don't find free enough, want to make things "modular", want to split development and base packages, want to support a ton of architectures upstream doesn't care about and want to integrate things in their historic tooling. It has introduced some severe bugs in the past.