If I'm not wrong, Intergrade, Yuffie's part, is just for PS5, so if anything that would be the only new thing you would get in relation to the PS4 one.
As for the Remake itself, so far there's only Midgar part, with some extra points in story, if I'm not wrong it's small details, great graphics and the combat system. Characters like Cid, Vincent and Cait Sith haven't appear yet. Yuffie just appears in Integrade, where she is the protagonist and Deepground from Dirge of Cerberus are the bad guys, namely Nero in this case.
You should probably wait for a comment of someone who has the Remake.