Honestly, even though this game was never intended to be a harem game or even one where you could "have 'em all" with little fallout but not end with all of them, I think it's really quite difficult to do any adult game and not have people wanting to end up with every single female character they fuck along the way.
The escapism of these games is so often predicated on the notion that infidelity and womanising will be rewarded and that even if it causes some friction/break-ups, it will always be salvageable, and it's hard to dispell that once it's ingrained in people's heads. You could make a game with just 2 LIs, have them say in absolutely clear English that they will not tolerate a guy who sleeps around and/or leads them on, and people will still hope for an ending with both of them.
Perhaps more games, including this one, should be including more consequential choices earlier on or perhaps even lean more into branching whereby you have to choose one girl over the other at certain points and this will determine your relationships, because one thing this game suffers from, which others do too, is that the MC can do pretty much everything with everyone in every episode one after the other, and because they can do that, it makes people feel like that can have everyone because no-one has to be left out or avoided and they're able to maintain all these relationships simultaneously. But if they couldn't do that and had to choose between one or the other throughout the game, then that could maybe go some ways to making it clear you can't have them all because your time is being split between them.