Basically both it and SMT have the same progression system, you could compare them to Pokemon and label them as monster collecting RPGs. The demons/personas are basically these mythological creatures that you equip to your characters, each has different skills. You get stronger ones by fusing them together, they inherit some of their skills. The life sim stuff goes hand in hand with that system because you can basically spend your free time hanging out with other characters, that levels up the social link which unlocks a tier of new personas to be accessible via fusion. Basically each activity from the life sim part of the game takes a certain amount of in-game time (there’s an in-game calendar) but the dungeons/regular jrpg gameplay are outside of time so there’s no time pressure really, you have events in certain dates
SMT is post apocalyptic and a bit more similar to regular JRPGs in terms of structure, Persona has very different vibes as it’s basically a playable urban fantasy anime. I doubt there will be a demo but whether you love it or not I think that it’s still the kind of game that will hook you, just like how some people that don’t care about traditional JRPGs love Pokemon. Expect some very slow beginnings though, I only played 3 and the actual gameplay loop started only after one whole hour, maybe more. They are pretty iterative in terms of mechanics and features so instead of grabbing 5 at launch you could start with 3 or 4 which will be cheaper and see if it’s for you