I played P4G long ago on my PS Vita, bought P5R on Steam a while back and I'm most of the way through it on my Steam Deck right now.
I love the story and the art for P5R but the game is a bit weak as a game, mainly in the way that other turn-based games (a genre I like) tend to be weak. Except for one battle, status effects mostly don't matter (just wait a few turns and they expire) Games with mechanics that don't matter are just so widespread: I think of Fire Emblem games where the weapon triangle doesn't matter because (i) it is so easy to overlevel characters, and (ii) if your characters is overleveled the weapon triangle doesn't matter.
P5R is a crazy long game that doesn't make you make any choices about which social attributes you develop or which characters you befriend, new game plus is unimaginable because the game is so long so you feel you have to do everything which makes the game longer. On top of it the game sets deadlines for you to clear various dungeons which are never challenging to hit.
... and it's not that it is a bad game relative to other games, it's one of the best, but playing through makes think that people need to make something really different in the area of turn-based games mashed up with visual novels such as shorter games that you have to play through to experience everything or games where every mechanic is meaningful. Back in the PS Vita era there were many games where I would really enjoy the NG+ such as Akiba's Trip 2 in which playthoughs got faster and faster as you got stronger or the Neptunia games which had first rate voice acting in two languages and NG+ meant you could enjoy both.