What could Sony first party studios be developing right now?
Bend Studio: their last game was released last year (Days Gone) and it sold very well, so they are probably working on a sequel . As much as I want a new Syphon Filter I don't think that's a possibility.
Guerrilla Games: Working on Horizon II: Forbidden West, but they hired some Rainbow Six Siege developers last year, including someone who worked on Killzone 2 so that leads me to believe they might have a second team working on a shooter game, I'd say it could probably be a tactical shooter like R6S.
Naughty Dog: They just released The Last of Us Part 2, they probably have a second team that was already working on another game. What could that game be? there are rumors that it could be a sci fi game. I doubt they are working on a sequel to Uncharted or TLOU so we might get a new IP from them.
Japan Studio: They are working alongside Bluepoint in Demon's Souls Remake, but the latest rumors suggest they're working on the new Silent Hill and if Moore's Law Is Dead's info is accurate and Mark Cerny is indeed working on a Sony game, I'd say Japan Studio is involved.
Sucker Punch: They just released Ghost of Tsushima and it seems it was a success, and I don't think they have a second team so whatever they're working on must be in early developement (New IP? GoT sequel?).
Pixelopus: They work on smaller scale games, their last project was Concrete Genie so I expext them to be working on something of the same scale, maybe a VR game.
Polyphony: They're working on Gran Turismo 7, and that's it, I doubt they have a secret project in the works.
Santa Monica: Everyone expect them to be working on a sequel to God of War, and that's almost a given. But I believe they have a second team working on another project (a sci fi game if the rumors are to be believed), and again, if Moore's Law Is Dead's info is accurate Cory Barlog could be directing this project and supervising GoW.
Media Molecule: They're busy with Dreams, and if they work on something else it would probably a new IP.
London Studio: They must be working on a VR game, maybe a Blood and Truth sequel or a brand new IP.
Insomniac Games: Their current projects are Spider-Man Miles Morales and Ratchet and Clank: Rift Apart, but I believe they could have another team working slowly on another project (probably Spider-Man 2 built to take full advantage of the PS5).
San Diego Studios: They must be working on the new MLB: The Show that is supposed to be multiplatform.
New studio working on a secret project: They are supposedly working on a "AAA third person action adventure game", that has led everyone to believe that it could be a new Uncharted game.
And this are just the first party studios, we know they have second party studios working with them, like Housemarque, Sumo Digital, Lucid Games and Bluepoint Games (which some say are working on another remake). Plus, It's pretty safe to say whatever Kojima Productions is working on it will be with Sony. Also, this might mean nothing but Shuhei Yoshida visited Remedy last year so... who knows, they might have something in the works.
All this makes me realize how much effort Sony has put on consistently delivering lots of games for their platform. Looks like games won't be an issue this gen.