Debian. I don’t see much benefit of Ubuntu LTS compared to plain old Debian. It’s exactly what you wanted.
Alternatively, AlmaLinux is a good choice if you like Red Hat stuff (RHEL clone), but the difference between Ubuntu LTS and Debian would be almost not noticeable for you I think.
Debian is community run, which often means all changes and features get implemented because the community wants that, not some corporation. One notable example of that is Snap.
Also, I found (minimal install) Debian a bit more minimalist than Ubuntu server, which is great imo. I just want the bare minimum for my services to work, and pretty much the only thing I expect from my server to have is SSH and Docker.