Stadium rank being inconsistent player by player

My duo partner is receiving 150 points towards his stadium rank where as I am only receiving 100. Being a player only interested in competitive modes this is deterring me from playing the game. We almost exclusively play together and he is ranking up much faster than I am. I’ve seen some posts on the internet stating that the MMR was based off of quick play, which he plays and I don’t, and that is why he is receiving more points than myself. Idk why I am being punished for not playing a competitive mode, when stadium is considered a competitive mode. I think it should be consistent throughout for all players.