There are FOSS alternatives available. Containerd, cri-o, podman, buildah, kubernetes.
About snap and docker. Don’t install Ubuntu on servers anymore, they are packing things in snap now instead of apt, people waste days figuring out why things don’t work and the reason turns out to be additional snap rituals required, ERPNext installation issues [docker] - #13 by EI-IT
If you use Ubuntu make sure things are not sneaked in as snap package.
Debian/Devuan is good choice.