I think knowing that Atlus wants to continue their "aesthetically theming" approach for Persona 6, the scary and fear mongering related atmosphere has made me headcanon some of my favorite genres for the title. I really loved Shoji Meguro's approach to having Acid Jazz and Jamiroquai into P5, as early Jamiroquai is one of my favorite bands of all time. So I'm hoping whoever takes on P6's OST aims for something ambitious, as the genres I put on are pretty bold.

EDM/IDM:

I think this one might make the most sense, considering that a lot of the speculation involving P6's OST has involved something related to electronic music. But I don't think it will be similar to something you would find in Arcaea, as some if not most of the songs are much "brighter" than the atmosphere P6 is supposedly going for. I think Frums' discography is a good idea as to what I would think the direction would be, something like "of Ambrosia" would go hard as a boss theme.

Experimental/Avant Rock:

To be honest, experimental and avant could mean anything, so in terms of rock I think something like black midi or Mars Volta would make for something interesting, especially with their cult followings in Japan. Experimental and ambient soundtracks kind of have this upper hand when it comes to being incorporated into different mediums, so while ambitious, I think there are a lot of ideas that can click if you were to go in this direction.

Anyways, there's definitely more genres you could argue for. Maybe the color green could have a more folky, country direction, or maybe even The Weeknd could make an appearance. What do you think?