Their infographic video says there are millions that have played this game but it does not mean they are active.
Millions of them are probably just downloaded the game from the advertisement from their favorite content creator, look at the game, probably leveled up to 10 to help the content creator, then quit. Also, they probably make another account just to reach the no. Of players required by the content creators.
Looking at the no. Of views of hellhades, chofly, etc. I don't think this game have 100k active players.