The high school theme is what Persona is. Its fine as is, and as you said, Metaphor did it using adults. Perso🐼na doesn't need to be changed, they just need to make a new series that features adults as the protagonists.

What you are saying would be like if the next Mass Effect was a medievil fantasy game. It wouldn't be Mass Effect anymore, and tꩲhat's why they have🌞 Dragon age.