After thinking about it some more, I think I realized that the main part of my issue with the current "Hana ending" is that it shouldn't be the ending we get at the end of the route where Tatsuki made all the "healthy" choices (not freaking out and rushing home during the play, ignoring Katsuo, and making the decision to let Yuma go so he can have regular relationships of his own rather than staying attached to his role in the play). This is going to be a bit long but allow me to elaborate.
Currently we have at least 4 potential "routes" and 1 "ending", the 4 routes are: Tatsuki's fails to keep his cool and rushes home, Tatsuki goes to Katsuo's onsen instead of camping with Yuma, Tatsuki keeps the play with Yuma going instead of letting him "leave the nest", and finally the route where Tatsuki avoids all 3 of those things. The only ending we have so far is the "Hana" ending where she becomes more dominant, more agressive with the teasing, and is given full control of the play.
Now, I will ignore the "Katsuo" route because I have no idea what Fallen has planned for it, but my proposal is that the current Hana ending should be moved to the "Tatsuki rushes home" route, while the current "all healthy choices" route should lead to something like a "Tatsuki" ending, here's my rationale:
I think that after the sex scene where the "Tatsuki rushes home" route stops, Hana and Tatsuki will need to have a serious conversation, Hana will be frustrated that Tatsuki put her in a difficult spot by surprising her and Yuma like that, that it forced them to rush into something Yuma may have still not been fully comfortable with, etc. But after expressing her frustration, Hana would take a much more caring tone and express genuine concern for Tatsuki, that maybe she pushed the play too far and that maybe they need to put a stop to it before things go sour. At this point Tatsuki would interject that he doesn't want the play to stop, that he already feels bad for the way he messed up and it would be unfair for both Yuma and Hana to have to stop because of his mistake, and not only that but he personally still wants the play to keep going, he knows that on the whole he has been happier with it and it has revigorated his relationship with Hana, but it is just that in some moments where the feelings of anxiety and jealousy become too much he can't control himself and ends up saboutaging something that was meant to make him happier, he feels pathetic in the way he just forgets what he truly wants, specially when it feels like Hana always knows better, and knows what he wants better than himself. From that comment we start developing towards a route where Tatsuki gives full control of the play to Hana and leads to the current "Hana ending", focused on maximum teasing like it currently is.
Meanwhile, the "all healthy choices" route could lead to a "Tatsuki" ending that could be more focused on the more wholesome plotlines, like the "starting a family" plotline. Could even keep most of the content currently as it is, I would just change it so that at the end of their play when Tatsuki fails to not cum, Hana still decides to let him see a "special video", except instead of it being Yuma assfucking her, it is actually a video where Yuma gives Tatsuki a heartfelt farewell that he would have been too embarassed to give in person, he talks about how initially it was a bit difficult for him to come to terms with the idea that the play was going to end, but that eventually he understood that's a decision Tatsuki arrived at while thinking of what was best for Yuma himself, and while he doesn't really understand Tatsuki's fetish, he knows it can't have been easy for Tatsuki to trust Hana to another man, and even then he still never did anything but take good care of both Yuma and Hana, he then concludes that Tatsuki is a good man and that's why Hana is his woman, he is nothing but thankful that Tatsuki was willing to share her with him.
I would then have a pregnant Hana cg of her being "caught cheating" on Tatsuki with another man as being the final scene of the "Tatsuki" ending, because they will continue with their play whenever they can but they also feel they are fully ready to start a family, while the other endings won't have a pregnant Hana because, while they are still planning to start a family eventually, it was put on hold for the time being due to the specific circumnstances of each ending. Yuma's ending could be something like they putting it on hold until Yuma is done with college because that's their initial timeframe for how long they want to keep the play going and they don't want the house to get "too cramped" (Yuma keeps living with them instead of moving out). Hana's ending could be because she teases Tatsuki that with the type of things she has planned for him, it would not be the most ideal environment to raise a child so they will put that on hold for a little while, until they are done exploring all the kinky fun Hana has planned.