As it it's a single most advanced deployed (mature) mil engine in the world. Especially in jet VTOL field, where China is an absolute newcomer.
F135s, for all their shortcomings, fly and power over a thousand aircraft.
Designs/technology are curse worse at this point.
Right now China, in production, is at WS-10C.
In American terms this is mid 1990s, which is 30 years ago. F135 is two 10-year cycles and full generation ahead of that. Maybe WS-15 is just around the corner (it is for many years), which will still put the situation in the same general spot, as through 1990s, F119s powered F-22 prototypes without major issues.
What's the point of "designs" - I'd guess any seriously competent engineering professor in this field from university in Tehran or Pyongyang will come up with a reasonable design. What matters is not that, what matters is deployment. And here F135 is solid ahead, as a finished step.
Of China, of Europe(yes, even with RR F136 in mind, which wasn't deployed), of Russia, of everyone.
You can't take a flight in an aircraft powered with forum/substack technologies. You need an article.