Harem content is optional. As for whether it affects the ending, I'm not sure yet.
All sexual scenes can be avoided after this new update.
big fucking pass then if this game is gonna have ntr, and just to be clear what this fetish does mean-->
NTR (netorare/netorase) = Any love interest (girls the mc can romance) having sex with someone else than the MC is ntr.
I know some cucks says otherwise (like the mods on f95, or a few in that site) but that is basically what you have to avoid, if the mc will be the only one having sex with the girls, then that will be fine.
You should be clear about this, because it being "avoidable" is still the same crap content.