I don't see Debian as a "server only" distro.

It is good at being a headless SSH-only infrastructure server, but it's also got a huge package set and many well-supported desktop environments, so it's a good desktop distro as well.

Ubuntu-based stuff is getting increasingly full of snap and ESM advertising and other rubbish I don't want.

Sure Debian might end up with older packages later in the release cycle, but it's not much different to using Ubuntu LTS as desktop, and anyway this is largely solved these days by desktop container tech (Flatpak, Podman Toolbox, distrobox, etc).