I'mDudditz!
Newcomer
Sony first party also have a reputation for really pushing the visuals so if they want to continue to have that image they might very well go for 30fps.
I feel it will also depend on upscaling, it could be FSR2 quality mode at 30fps and FSR2 performance mode at 60fps (But using FSR performance mode at 30fps will give them hella lot of power for insane graphics)
Although I'm really shocked we've not seen an ML based upscaler on the consoles by now, especially the Series consoles.
Maybe just you. God of War Ragnarok uses ML TAAU on 1440p base and yields pristine results better than native 4k.