By J-20 I mean J-20 family. J-20 can upgrade avionics to J-20A standard if needed.J-20 is a 2017 aircraft, 2018 in it's current form(more or less).
Expecting the same level of stealth and avionics from it as from a 2025 aircraft is quite... optimistic.
What is J-20A in this case?
Flankers aren't stealth. Was proven again just today.
They can do stand-in, which is much, much more.
And they can launch stand off from their bays, too. Just smaller.
At the current rate, J-20A or better will make up 70%+ of J-20 family at production ends. It's the opposite of J-10 production run.
As for stealth, I believe as long as they are in the same league, incremental improvement it's not that important.