there were four screens on the promo right, so let's assume there are four projects. one is obvi a switch port and one is obvi a fighting game, so that leaves two mystery projects. they've already done the dancing game, anime, and pq2, so we can rule those out.
worst, but most likely case scenario is that one is a Joker Smash Gameplay Reveal + Shadow Drop and the other is some kind of mobile game. (and while a lot of people would be hyped for a Joker Smash Gameplay Reveal + Shadow Drop, it's also, like, not really taking the Persona 5 franchise into a new and interesting direction)