>>39802332both are turn based jrpgs that lets you collect mythological creatures.
the main difference between the two is the baseline of the story and some core mechanics
in SMT the world is fucked and there are demons all over the real world. get ready to have your moral compas tested (at least in the better games in the series)
Persona tends to go on a lighter note and focus more on the "meta" world and commentary with more involvement of the psyche
on that note knowing that there is almost 0 chance any of the chuubas i like will play strange journey is fucking soul crushing.