rig does support derivative distros, but you need to set the
RIG_PLATFORM="ubuntu-24.04"
env var, so rig knows which OS its needs to download packages for.
But again, we only build R for Ubuntu LTS versions, and not for the other releases. Posit Package Manager also only builds binary packages for Ubuntu LTS releases, so it is really beneficial to use an LTS release, if you can do that.
My experience is that our LTS packages do not work on the non-LTS releases.