Mint removes everything that makes Ubuntu bad and they have a version with the same features but Debian based and because Ubuntu is pushing snaps so much they have been thinking of making LMDE (Linux Mint Debian edition) the new default
Fedora is moving a bit faster than Debian(but it’s pretty unstable), the main selling point is in my opinion dnf/rpm, but on a server a rhel clone would be a better choice. Pop OS and especially Mint are great distros, Debian is great but very outdated, I would try them live and then decide
Snaps is Ubuntu/Canonicals proprietary package format which is mostly considered a worse alternative to flatpak (another package format) with no real advantages on desktops that Canonical is trying to force on users