played the game
not too deep (with ntr ON as some said the path doesn't feel like it) and that seems true as i didn't see any NTR there , it more like a Soft NTS (MC already have the power to see her cheating activities and he enjoys watching it , he is the reason for that route anyway by pushing her limits , while ntr should be the opposite , he shouldn't enjoy and be okay with it or even knows lol).
the only NTR i can think of is if his fiancée started to develop love interest for mark , and Mark will try to steal her before the official engagement happens , but with his power he can easily reverse everything or even manipulate Mark to get into men instead

, Unless Luke (the spirit or whatever) have a say on it and make MC
SUFFER (which is the real core of NTR).
For the Grind , there is a skip button , just check the Journal for when events will happens exactly , but at same time you might miss the encounters with other girls .
Story could be way better with 3d (even Ai) instead of different real models that kills the atmosphere.
(Game needs Netorase Tag on the OG page as it has sharing)