So, to ask this question in another way: what is projected to happen if you play the game by maxing the beta points, or by not actively opposing Big John? Does he have his wicked way with the girls? What I am asking is, are there playable stakes in the game (ie, a contest between you and Big John for the affections of the girls)? That, in my opinion, is the best way to make a compelling game in this scenario. Again, just an opinion, but the stakes are the key: total victory or unconditional surrender. And everything should be seen: the MC building his harem, or watching Big John do it. That is, if the girls are simply victory conditions for the MC. If he only gets with one and protects the rest, then those are the stakes.
Dev has forthrightly stated that he will not change his story for anybody, and that is just fine. The above is an opinion and hopefully a way to clarify the path of this game without being subjected to the eternal war of "NTR/no NTR."
So, having run through it, this could get exceedingly dark. My preference is for this not to happen, but the warning is there at the beginning. Regardless, good luck.