4K 60fps mode without RT is the most likely scenario.
To my understanding HW RT gives developers a certain amount of rays they can use for free, so theoretically RT shouldn't affect performance that much. For example metro exodus has really small performance penalty (just 3-5fps worse) with RT if you will only ballance RT budget correctly (resolution change the amout of shooting rays). Developers on PS5 optimize their rays budget to something like 1080p 30fps (upscaled to 4K), so in order to reach 60fps they would need to shoot 2x as many rays. They will most likely turn off RT in 60fps performance mode.
There is one game on PS5 that will run at 4K 60fps with RT, but gran turismo 7 will use even lower resolution RT reconstructed to 1080p and then upscaled to 4K.