I was basically thinking along the same line as
@Brockstar here. I remember being completely perplexed that Stipe wasn't going for a RNC. I haven't seen the fight in a very long time, but I just remember the door being open.
I agree with you
@HockeyBjj that it's unlikely, and it wouldn't be worth anything more than a small play. But if Stipe is to execute a similar game plan, and Ngannou hasn't improved his ground defence, it seems like an obvious PTV since it's a low skill option that you've gotta think his coaching team has pointed out to him. It might be his easiest PTV, even more than GnP