well about tags, NTR tag is the most terrible tag ever made on this forum. Everyone uses his own definition of NTR, some think rape is/isnt NTR, sharing is/isnt NTR, some think humiliation is/isnt needed in NTR, some think Mom have sex with Dad is NTR if a game has incest tag. If you are a dev, you 100% won't like to use this extremely confusing misleading tag.
The dev also wouldn't want to limit themselves to tags if they are still planning on future content.
It is also quite pointless to talk about possible optional future content that may or may not happen and may or may not be delivered as DLC content. We can't really discuss something that has not happen especially when we have zero information how it would possibly go. Would it be rape? sharing? humiliation/cuckold? mom and dad having sex or sth else?
If you are that bothered by NTR you should actually contact the devs through patreon so the devs know what their supporters think. In this forum's current environment, any NTR discussion would only end up with pointless kink shaming and flaming that leads to nothing but hate.