Have you actually seen any supporting evidence to make such a conclusion? We know from Red flag exercises, that the F-22 has superior SA and in every engagement it has been able to dominate. How it is able to do so remains unknown. There is no exercise conducted yet that pits a F-22 against a F-35 and so we don't know how each platform using the respective strength of their electronics in such an engagement will turn out. We know completely zero about the J-20 avionics capability. There seems to be a major assumption that the Chinese has completely caught up. I would like to see some evidence to actually support such an assumption.
Yes, that is why I said "mature" -- i.e.: a J-20 with a competitive avionics suite (not to mention WS-15s over Al-31s). I also mentioned mature/upgraded F-22, i.e.: upgrades that leverages advancements within the last decade in avionics technology applied from the F-35.
In other words, that theoretical comparison is deliberately holding the avionics suites of the various aircraft to be relatively equal with the differences being their kinematic and other physical parameters (weight, speed, etc) to be the important factors for comparison.
Trust me, I'm not making any assumption "that the Chinese has completely caught up," but it is a hypothetical for the sake of comparison to highlight the important differences between the various aircraft aforementioned which cannot be upgraded.
Nowhere have I said that the Chinese have yet or will imminently "catch up" (though at the same time I've not said anything to the contrary), nor have I sought to apply the comparison in any real world way as I was pretty clear that it was theoretical in the last post.