There's a big difference between the two games: FM7 supports crossplay, so it counts both PC and Xbox One users.
That doesn't mean that it's the best game or the most played, but that almost every Xbox One X owner bought the game with the console since at the time of its release FM7 was THE Xbox One X showcase title.
I'm playing it on a standard Xbox One, it's a fun title but it's still the same simcade, nothing new, only a bit improved compared to FM6, and there are far better sims out there.