With how much of a darling that both Metaphor and Persona 3 Reload were for Atlus, both of them being their fastest-selling titles, I could see them getting representation in the next Smash game in some form. Maybe Metaphor will get a DLC fighter with or without a Switch 2 port? After all, the lack of a Persona 5 Switch port in 2019 didn’t stop Joker from being the first character revealed for Fighters Pass Vol. 1.
That way, you can sort of present the bonus DLC character in the literal "a wild ??? appears!" sense depending on which way around you do it, literally presenting it as a surprise encounter, while the more popular Pokémon pick is already in the base-roster. Or something like that.