You can upgrade from CentOS 7 to Rocky or Alma:
https://docs.rockylinux.org/guides/migrate2rocky/
https://almalinux.org/elevate/
I can't imagine that working well with Virtualmin, given when I DID replace my VPS I couldn't use it on Alma as it was not supported due to distro differences in paths. Granted, that's a Virtualmin issue and I ended up with Rocky which hopefully can update more seamlessly.
