It stands to logic that Chinese military technology will slowly catch up with the US over the decades to come. China has a massive and growing economy and very talented scientists and engineers to propel it's military technology forward.
There is no precedent in history of anything otherwise as the one catching up always can learn from the leader in one way or another.
Chinese had enjoyed unprecedented access to American centers of learning and technologies through the years - much could be learned and replicated in due course. It was easy to catch-up under these circumstances.
Now that the Americans are adopting measures to curb the aforementioned, Chinese will have to develop their own solutions to cope with emerging challenges and more. I am sure that the Chinese can chart their own course to glory (talented people on average) but they might come up with radically different approaches to fulfill their needs much like USSR had been doing.
Let us see.
As an example, the US gave away the shaping of stealth planes to minimise radar returns. It is estimated that 80% of stealth comes from shaping and the rest from materials in the airframe.
All China had to do with J-20 is copy these shaping priclnciples but has had to come up with their own materials for the airframe from scratch.
Complex mathematical equations coupled with computing advances to process and analyze radar returns to mitigate RCS reflectivity inform and/or serve as the basis for VLO compliant geometric shaping in theory which in turn is physically constructed using enabling stealthy applications to achieve VLO results. This is CLASSIFIED domain of work in large part.
The Mathematics of Stealth
maths.mq.edu.au
Although, crucial documents can be sourced through espionage at times, implementation challenges come into play next. Prerequisite infrastructure including tooling facilities should be in place for the needful.
There are reasons as to why F-22A Raptor could not be CLONED by another country - both Russia and China came up with their own respective designs lately. Although, China is doing much better than Russia in this matter. However, China is still coming up with relatively different designs than others.
I actually think that even as early as 2030, US ability to protect Taiwan from Chinese invasion may come into question. By 2040 China is likely to have the upper hand.
For China to attack now when they are certain to lose if the US intervened is the height of folly. Better they wait as the military balance will slowly turn in their favour.
REPEAT - This might be the impression in Public discourses but WE cannot be sure about this. American military advances have taken a more concealed course lately and even minor leaks in the Public domain suggest remarkable gains from current level of capabilities which are still a decade ahead than closest competition on many counts.
There are political considerations in this matter. USA is less likely to intervene for Taiwan for as long as it see value in its relationship with China. This might change in the coming years. There are already signs of de-coupling in effect.