Without thinking or reading to the last paragraph of this article, I went and started a dist-upgrade on my pi.
Curious now to see if it still boots after it's finished.
Edit: Oops
~ » ssh pihole@172.16.0.1 Last login: Wed Oct 11 09:38:31 2023 from 172.16.0.96 compdump:print:36: write error: no space left on device compdump:print:42: write error: no space left on device compdump:print:44: write error: no space left on device compdump:44: write error: no space left on device compdump:print:44: write error: no space left on device compdump:44: write error: no space left on device
One thing Debian introduced recently: apt upgrade --without-new-pkgs and they recommend that before a full dist-upgrade. I think it's made a pretty big difference in the upgrade smoothness, eliminating some possibly-breaking package upgrades.
As a followup, I just changed the repos and did the apt full upgrade. Everything works beautifully. But as I said, I had a very minimal headless install without any DE.