Is it time to move from a Ubuntu base to Debian?

The Zorin brothers and very little factors in regards to any consideration

None of this would change, Zorin is already built on Debian.

There are already multiple choices of the same program, deb, flatpak and snap.

I'm not sure you are understanding. Ubuntu is already Debian, therefore Zorin is already using Debian. The only thing that would be happening is instead of waiting around for Ubuntu they would only be waiting for the Debian release from Debian itself.

Going from Ubuntu to just Debian is easy and you would not even know it, because it is the same system just minus all the stuff Ubuntu adds.