Let’s be real, 99.9% of female protagonist games are just corruption games cosplaying as NTR games.
To be fair, a lot of "NTR" games in general are simply corruption with MC playing the role of a casual observer or narrator.
So I don’t think it’s a symptom of female protagonist, but of "modern NTR" as a whole.
NTR isn’t really that niche anymore, and many adult devs have tried to cash in on it.
This has led to the phenomenon of "fast-food" NTR made for quick faps and minimal thinking. Instead of developing the NTR, the author "assumes" the reader has a pre-existing affection for the FMC. Which of course, hardly works when you barely know the characters. You’re fapping to the pixels, not to the story in that case.
In the end, it’s difficult to even call these works "NTR" because the protagonist is often underdeveloped and unrelatable. I
s it really genuine NTR if a bull “steals” a random mob character’s partner away?
Now, if you want games with a female protagonist (and strong NTR feeling), Curse of Kubel is high up there. Accursed: Emma's Path is good too. I’ve played a few more, but my terrible memory is not helping at the moment. xD
Oh, and my game has a headstrong FMC, I guess. While you play as Akari for half the game, the MC is also no slouch when it comes to his girl(s). MC and FMC have a pretty sweet moment in Chapter 5, which I can’t wait to crush in Chapter 6 & 7.