I don't want to verge too much out of topic, but early talk and speculation of 7th gen characteristics is about extreme altitudes/near-space operations.
It's speculated this way since mid 1950s... count me very sceptical.
Fighter - as opposed to interceptor, interdictor(word best suited to describe J-36, btw; IMHO of course), penetration bomber, etc, - should be able to fight in all situations and at all speeds. Sometimes you intercept supersonic jets at 60k feet, sometimes you fight helicopters at 600 feet, sometimes you escort a transport aircraft, sometimes you loiter for hours just in case. Sometimes...
And it's just impossibly hard to mix extremes with existing propulsive tech. Like, mig-31 is already a big trouble in WVR for everyone, despite it not really being built for WVR
fight (fight being a situation when enemy can fight back and you have to do something about it).
But as a fighter aircraft(not just interceptor with part-time killer job) its just hopeless.
This doesn't mean such near-space fighters won't appear - like, if nearspace travel will appear as something more serious than sci-fi, technology will have to match new rules of medium. If mr. Xi flies on CZ-9 in a state visit with remote risk, he'll need escort.
But this is
in addition, not
instead. You can carry passengers with CZ-9, but loitering or providing CAS with it will be quite hard.
So for now, J-36:
(1)Interdictor - long range, theater maneuver speed, broadband VLO; air or surface targets regardless. Enemy theater order of battle disruptor.
(2)battlefield aircraft - there's a lot of optimism for it as a command node, though frankly i don't think i see it. It can do it, probably better than J-20S. It's still not worth it using such a valuable plane for it over available c&c nodes, unless situation calls for it.
(3)interceptor - not exactly built for the role, but again, why not. Speed is here, loiter is here, weapons are here. High T:W and stealth will be wasted, but sometimes you need to do the job, not complain about margins and efficiencies.
(4)fighter. I don't think it can't do BCMs - and it certainly can do very long range escort better than almost anything. Ultimately, if you have side sensors and corresponding level of picture - you can fight with offbore weapons. Not the most energy-advantageous way, but it's a way.
It's just unlikely to be good at WVR BCMs(no vertical surfaces is a con, no way around), so, say, forcing annoyances away without shooting them down may be hard.