Personally I'm in the "The new Nepeta from the intermission in Beyond Canon is Ult!Nepeta" but I know other people think its a different kind of Nepeta. I lean more towards it being Ult!Nepeta though because of how that whole section seemed to play around with meta, and I just feel like Nepeta herself would have to have that knowledge in order to play along. I don't think a Nepeta who was just simply alive would narratively make sense there is all.

That being said, if that is Ult!Nepeta I think she will serve as an example to those who haven't become their ultimate self yet that Dirk isn't setting. If what Dirk did to become an Ultimate seems horrifying, perhaps whatever Nepeta did will be less so and SHE'LL be the one to nudge the others into potentially "leaving the cave">