It's funny because I remember when NT00 originally finished the story, people were really wanting a wholesome ending with the MC and Yumi in his comment threads. So that it would just be Netorase and not hardcore NTR ending. Which is technically what we got originally with the two of them ending up together as a couple. A "happy ending".
I recall NT00 saying they were unsure of what they really wanted to do with the direction towards the end, so they continued to keep making what-if scenarios and that's also when they remade/updated the entire story to what we currently have. But it definitely seems like the spiral into inevitable and true NTR is what we're going to get by the end of this story arc.
I feel like if NT00 gets scared and decides to pull out and give us a "happy ever after with the MC" when we're already this deep into the Netorase/pretty much NTR "play" at this point, then it'd kind of feel like a cop out. But a "happy ending" for the "true ending" could happen because they've been making separate "Sadistic Yura/Yumi" side content which has been actual NTR/Femdom. Personally, I'd be fine with whatever, but for storytelling purposes, the MC should face the consequences of his choices as a cuck for the true ending of this arc imo.