I spent too much time looking into this as I hardly use my PS5.
Going by that tweet, saying a Playstation game "they" are making, I assume Sony / first party.
Bend Studio - Last title was Days Gone. Have had job listings out for people specialicing in vechicles and is currently making an "open world game featuring vehicles". Maybe?
Guerrilla Games - Killzone / Horizon Zero dawn. Making Horizon 2. Not this studio.
Housemarque - Just released Returnal. Not this studio.
Insomniac Games - Spiderman / Ratchet and Clank. Just released a new Ratchet. Not this studio.
London Studio - Singstar. Indies. Not this studio.
Malaysia Studio - Support studio. Aquired in 2020 to aid other studios with titles. Not this studio.
Media Molecule - Little big planet. Dreams. Doubt it is this studio.
Naughty Dog - Last was TLOU2. Could be them, but highly unlikely unless they just show a CGI trailer of something they are working on coming in 2023 at the earliest.
Nixxes Software - ? Not made anything since they were aquired. Specialized in porting games. So nothing new. Not this studio.
Pixelopus - Indie. Aquired by Sony. Has a TBA game coming, but studio too small to be a "big" title.
Polyphony Digital - Gran Turismo. Already announced. Not this studio.
San Diego Studio - MLB. Sports. Not this studio.
San Mateo Studio - Co developer of games. Not this studio.
Santa Monica Studio - Making God of War 2. Not this studio.
Sucker Punch Productions - Infamous. Ghost of Tushima. Doubt they have anything ready yet so probably not this studio, but do have listings for a multiplayer game.
Team Asobi - Astro's Playroom. Indie. Not this studio.
Xdev (Japan/London) - Previously a co-developer (Returnal, Detroit Become Human), but in 2020/21 they were boosted into a studio. Has joblistings out for people able to make AAA games. Doubt it is this. Too new.
So, contenders then.
Xdev (unlikely a new studio would have anything remotely ready by now).
Naughty Dog. Been a while since they probably started on something. Dev name big enough to create waves + get resposibility for something AAA big anouncement, but would be ages away based on how long they take.
Sucker Punch Productions. Multiplayer game. Maybe? But not sure what would create excitement to make people lose their minds. That sounds like a game from something that is already established, and not aware of any high hype multiplayer games Sony owns. (EQ remake!....)
Bend Studio fits. Big enough studio. A while since last game. Job listings fit with an established Sony trademark that people are excited about (Twisted Metal). Open world version of that = bad ass and would be immedialty raised to a very high hype status due to being a beloved franchise that people want to come back. Fits tweet.
Could be you are right Spronk.