Certainly sounds like one.
Okay, I'll try to make a mathematical argument:
"In mathematics, set A is a subset of a set B if all elements of A are also elements of B; B is then a superset of A."
I kinda see minecraft as a squarified approximate superset of so many games. I mean you could probably play fortnite on some minecraft server or mod, but the opposite claim does not hold. So, under that assumption, If minecraft has greater or equal amount of content that you like (which you specified as fortnite content) I'd say it qualifies as being 'better'.