So, is there any real reason to revisit the older Persona games before playing P5? I played Persona 1 once on an emulator, and didn't find it very interesting, but I remember hearing good things about Persona 2 (the fan translation) and P3 and P4.
I've played all of them so I can give you a simple rundown
p1 didn't age at all, while the story and characters were really interesting, it has the plot like persona 4 i.e. realizing your true self but done better imo.
p2 duology is my fav in the franchise so I might be biased but it has the best story and characters out of all franchise, it divides one game into two parts, treating the silent protagonist of first part as an active NPC of 2nd which gives a ton more depth to the silent protagonist, I really like this thing in the game. Though, I can say for sure it's honestly the darkest persona in the whole franchise, I wanna go into details but that means spoiling the story.
p3 is more on the lighter end in comparison with the introduction of socials links and stuff but still manages to retain it's overall theme of 'death'. My only complaints with this one is the pacing and the dungeons. Like p2, I absolutely adored the characters.
p4 is even more light in terms of its themes, but good nonetheless, (honestly it's my least fav game because there are things I'm not a big fan of, subjectively speaking. That's why I'm not speaking much haha) Tho I'd say it still has the dungeon issues, while it tries to improve from persona 3, I still dislike the random generated dungeons.
p5 when it comes to presentation, it's my absolute fav, the game's aesthetics are a jam, the dungeons and the overall presentation of the game is top notch. I absolutely love the return of demon negotiation from the smt games and overall a decent game imo, the story's good nothing special imo but the characters felt more distant then ever. (I haven't played royal so I don't know if they have changed anything in this department)