"Gene Ranks" are not cultivation ranks. They are the speed at which a cultivator progresses through the cultivation ranks, if at all.

Gene Rank 1 is the slowest, Gene Rank 10 is the fastest.

Simply because someone has a Gene Rank of 10 doesn't mean they're guaranteed to reach the highest level. They could cultivate super quickly to the mid ranks and then stop completely (though that's super duper rare)

The cultivation ranks are split between 3 realms:

Ke --- Low Ke, High Ke

Masu --- Beginner Masu, Low Masu, Middle Masu, High Masu

Kan --- Low Kan, Middle Kan, High Kan