Certainly makes sense, but my guess is there are indeed multiple things in the works (like that rumored Dumbledore/FB TV series) but they're really early in development. It is unusual these days I feel for the creator to still retain the rights, so it must be frustrating for some of the big wigs at WBD but very, very good for Jo. We know Zaslav met with her in person, and that before that (early last year), he'd publicly spoken about his appetite for Wizarding World TV series before Cursed Child entered the conversation.
My idea is that Jo has all the power here and they're going to have to keep her very, VERY happy if they want her to give them even just a few crumbs. That's why I think, aside from the few clues we got (and the fact that TSoD is the third most watched film on HBO Max in 2022, and the first two films were also consistently in the most watched films leading up to its release, during, and then around the release on HBO Max as well), that the FB TV series is very real. Jo can leverage that, continue Fantastic Beasts the way she sees fit, a TV series being so much of a better fit (as much as I love the first two films and really like the third) for it, and then she can give them that, and perhaps other TV series in return.