Beyond being used as a long range anti-force multiplier role and beyond being a stealthy forward sensor platform, I think there's no reason why it can't act as a general air superiority aircraft in its current role where it leverages its combination of stealth, long endurance and avionics to nail opposing fighter aircraft as well, even if they are not opposing 5th generation aircraft.
And even with the current less than optimal engine set up, I imagine J-20As would still be the air force's most capable overall air superiority platform against all potential opposing fighter aircraft whether they're 4th or 5th generation.
The question is about where the deployment of J-20A (or WS-15 equipped J-20) would be most cost effective, and in that regard I agree that it would make sense that targeting the opposing side's force multipliers would be a significant mission of theirs, but probably only one significant mission among a number of other significant missions, and also it won't necessarily be that much more or less of a mission for them than targeting Chinese force multipliers would be a mission for US 5th generation fighters during a conflict as well.
The discussion about J-20A's role as an anti-force multiplier platform I think is often framed too much in regards to preconceptions about its capabilities that have been put forward by English speaking defence media, which leads to an incorrect conclusion where its role is limited by its capabilities IMO -- instead, I think the discussion about J-20A's role as an anti-force multiplier platform should be discussed within the context of force structure and the number of J-20As in service when a hypothetical conflict occurs. For example, I can envision that when only one combat capable unit of J-20As are in service that the air force would use them heavily in the most cost effective way they can, like to try and destroy opposing force multipliers. But when many more units of J-20As are in service, I imagine only a smaller portion of their sorties would be used for that mission as only a certain number of J-20A sorties would be judged as necessary for completing that mission and in the meanwhile there would be a large number of opposing 5th generation fighters taking on your own 4+ generation fighters which could use some friendly 5th generation support of their own.