This was the claim I made:
Since you disagree, are you are saying the J-20 is likely capable of performing cobras and J-turns?
I absolutely believe that J-20 is capable of performing cobras and J-turns in the same way that standard J-10A/B/C and standard PLA/SAC Flanker family are, yes.
J turns and Cobras are not that unique for modern aircraft capable of high AoA and from 4th generation flight control systems.
However that doesn't mean you would perform them routinely at an air show; OTOH a TVC equipped aircraft performing such maneuvers is far more normal, restrained even.
I want to again make it clear that if you are comparing J-10B TVC in isolation versus J-20 for these sorts of maneuvers, then you are doing so from a wrong basis.
Instead, it is J-10B TVC versus J-20, J-10A/B/C, SAC's Flanker family, J-35/A etc.
AKA -- it is difference of TVC equipped aircraft, versus, aircraft without TVC.
(A brick with a TVC engine could probably do a J turn and cobra)