Well, we can come up with some "archetypes" - and see if they match with different airforce requirements.
I won't write "sensor fusion", "integration with loyal wingmen" and "datalinks". That's a given.
By 6th generation for this post, i don't really understand something specific - different countries, different requirements, different everything. Simply a generation of manned stealth fighters, which will appear roughly in 2030...2045. Nothing spectacular, no quantum disintegrators, only tech within a visible event horizon.
For example, imagining a couple:
1. Heavy air superiority/multirole type - basically next-gen evolution of F-15/F-22 line.
Twin engine, 35-40t MTOW class. Likely supercruising/maneuverable, broadband stealth, focused on onboard sensors, larger amount (numerical) of internal armament, and lots of onboard power/(DEW, EA).
Focus: OfCA capability(all engagement ranges).
Likely for PLAAF/PLANAF? No for now, J-20A is new and fresh(the cutout date of 2045 is within 20 years of its introduction).
The likeliest candidate - USAF NGAD obviously, F-22 is close to 20 yrs old and lacks future prospects.
2. Light multirole type - F-16/J-10 replacement, "numbers"/exports fighter. Cheaper to operate than the heavy 5-6 gens and F-35.
Single engine, 20-25t MTOW class. Likely (but not necessarily) all-aspect stealth, missile-focused a2a, everything else - if possible.
Focus: staying within budget; supplementary anti-air and ground strike.
Likely for PLAAF/PLANAF? Yes, for PLAAF. J-10A is 20 years old, some sort of replacement shall appear no later than within 15-20 years. Given the strategic context - much like the J-10 itself, heavier emphasis on a2a as opposed to a2g is quite likely.
Quite likely the USAF will go for such a fighter as well, unless Lockheed will suddenly make F-35 affordable.
3. Heavy multirole/fighter/interceptor type (different from #1) - oversized payloads carrier. Su-27/F-14/Su-57ish probably.
Twin engine, 35-45t MTOW class. Likely less focus on stealth(but still stealth ofc), more - on very large payloads(hypersonic VLR a2a/a2g missiles, EW/ELINT/DEW pods). Otherwise similar to #1(supercruising/maneuverable, onboard sensors, lots of onboard power).
Focus: OtH engagement(DefCA), long-range strike, support of all sorts.
Likely for PLAAF/PLANAF? Yes, for both, but. Yes - because the role is clearly here, J-11/15/16 fleets are here, basic J-11 airframe and design dates back to the 1970s. Also yes because too many things just don't like nor require to be in, but still require an expensive platform that benefits from a crew onboard. Finally, yes because the J-11/16 airframe(hence: role) is clearly liked by PLAAF.
But there are butts.
Firstly, while PLANAF is likely to be in - they probably aren't quite sure themselves, how much. They probably want to understand what J-XY is and what it isn't first. If it'll do great with external payloads, provide enough power, and range will be sufficient - why bother?
Secondly, while J-15/16 airframe ain't new (D versions, in particular, are shiny new!) - there is not too much wrong with it, either.
Then, at least for PLAAF, there is a new shiny J-20S, too. Using it this way sounds a big wasteful/inefficient, but used it can be.
Finally - there is Su-57e available, which looks like a perfect fit for the mission. It isn't 6th gen, but it isn't big deal for carrying boxes. If su-27/30 could become J-11/15/16, so Su-57 can turn into hypothetical J-21/25/26.
Archetype is very like for US as well - USN's NGAD (and F/A-18E/F/G replacement) currently appears to be just that.
...and so on.