This upgrade which Russians are offering is derived from their Su-35 upgrade programme, known as Su-35SM. It will have GaN based AESA radar, QWIP based IRST, composite skin, better engines and reduction in frontal RCS with use of EWP.
By all accounts, the Su-57 still carries a GaAS AESA radar. I'd imagine any GaN antenna the Russians develop would first go onboard the Felon before anything else.
Now MiG apparently had offered an AESA Zhuk radar for the MiG-35. But the prog appears to have been scrapped after the jet failed to make the cut.
And EWP for Su-35 is a stretch. Structural RAS/RAM for the airframe or even spray-on coatings for the weapons I could see. But, EWP? Nope.


. No need to take my words as Gospel.