I get being annoyed by this, but imo the popularity of the question speaks to how much it matters to the playerbase, and as a result, at least in my opinion, the importance it should have to devs who depend on this playerbase to make their game successful.
Trust me I know it can get ridiculous, but the reason people don't bother making a distinction is because they don't care, as it is all several overlapping circles related to each other, hence why NTR is colloquially used as an umbrella term. Add to that that many devs themselves are very loose with the term and crossing the lines, and most players just don't want anything to do with any of it.
https://attachments.thef95zone.info/2021/05/1231446_1621832435820.png
Typically in entertainment media, and especially in the minds of a lot of players, NTR almost always includes the obvious love interest(s) even if they're not formally in a relationship, as it is a well-known and established trope which essentially suggests this person is
meant to eventually be in a relationship with the MC. It's different if it's a random person that is clearly not set up to be a romantic interest.
So while I do agree it's too broad, I also think that in part is a self-defense from devs who have also become too vague and casual with a fetish a lot of people dislike. So for a lot of people, if the crush is an obvious love interest, then this would definitely count as NTR.
I also don't think it's fair to be mad at people about this, as it's borderline kink shaming. People clearly just don't like NTR, and people have the same reaction to other kinks. No one is going to care about the semantics or context/nuance of anything that seems like rape even if it's 'technically' not really rape, they will still avoid it with a 10 foot pole, period.
This already a bit too long, but one last thing, it also serves no one to not just be blunt about this and let people decide by themselves. You clearly know people think of this as NTR (and personally, I don't think it's "new" NTR, it's cleanly in the long-standing broad definition of it as a fetish), so IMO it'll help you to get this over with now so you won't get angry people later worsening things and are far more likely to only draw people who come into the game expecting or even wanting what you're offering.
Just my... like 10 cents, lol.