I'll just add my vote to The Last Sovereign. It's an absolutely fantastic game with an outstanding story. Also, the main story is now finished, so it's a great time to start playing it!
However, it does take a good bit of commitment: My current playthrough sits at 112 hours, and I have the bigger part of chapter 5 still ahead of me (the last but biggest chapter of the game). I think you'd need to speedrun it to finish in under 100 hours. And I would
not attempt playing the game without either help from the wiki, or taking extensive notes.
As for NTR, the characters that do that are Succubi, for them sex is food, and everybody concerned views it as a positive event. It
really shouldn't be a problem. By then, the game has drawn you way too deep into its world.

(There
is one point early one where you have the option to prostitute an LI for money. It's a big choice with long lasting consequences, neither choice being obviously the right one. Basically all walkthroughs opt to not prostitute her, weighting the LIs trust higher than the money.)
I really enjoy the philosophy discussions in this game, the proactive planning the MC and his allies do, the worldbuilding, the characterization of
everybody (MC, LIs, allies, enemies, gods, normal NPCs, everybody!), the amount of agency you have. In my eyes, this absolutely belongs in the list of story focused games.
Yes, there are some sex scenes that aren't needed for the plot, but I'd argue they are needed as examples of the sex-positive world this game builds. And all sex scenes are short, easily skippable through (you can even disable the images), and their duration absolutely pales in comparison to the play time of the whole game.