OK. Where are then the extra antennas and electronic pods to suits that role?
There was never any expectation for any extra antennae or electronic pods for that role, because it would use the same avionics and networking suite as the single seat J-20.
The more capable command and battle management capability of the J-20S relative to J-20A arises from its second crew member, not from a more enhanced avionics suite, because the inherent sensor fusion, automation and networking capabilities of a normal 5th generation fighter are already so formidable.
Where are those videos of the 20 making at least mundane aerobatics?
Is the lack of video footage of J-20 making "aerobatics" your basis for suggesting there are somehow inherent flaws with its aerodynamics?
Come on, give us a break..
Next you're going to say there's an inherent flaws with J-20's weapons suite because we haven't seen videos of it launching a missile.