No, that is a poor metric.
If PS5 Pro uses PSSR to hit 60fps while offering slightly worse image quality than base PS5 achieves at 30fps, then image quality is a poor metric to gauge performance between the two machines.
It doesn't work that way.
PSSR might require a HIGHER input resolution than what base PS5 is using to achieve it's most effective image quality output.
Which may mean that there's no performance freed up just by using PSSR.
Because it's a poor example to use considering PS5 never hit native 4k in demanding games now.
It's pretty simple.
A game that drops below 1080p on base PS5 is likely going to need that base resolution increasing to get a good image out of PSSR, there is no performance increase here.
A game that runs at 1440p on base PS5 can have it's resolution dropped to 1080p for PSSR, this will enable a performance increase.
The issue is a lot games now can't even hit native 1440p.