It's not all that much, but Version 1.02 appears to iron out some annoying bugs that may or may not have been impacting your own experience. First, it fixes an issue where the screen dims during gameplay, and the second fix resolves a network error occurring under specific conditions (via Nintendo Everything).
Since Persona 5 Royal arrived on the Switch, Xbox Series X|S, PlayStation 5 and PC last year, it's already generated more than one million sales. If you've not already given the game a go on Nintendo's platform, we highly recommend it:
"Persona 5 Royal remains a game that we absolutely recommend you pick up as soon as you can. This easily stands as one of the very best RPGs of the last decade and you’d be doing yourself a disservice to miss out."