Medical science, semiconductors, jet engine materials are all things that requires time and money.
I would actually place medical science as the most difficult.
China will get to EUV machines and WS-15 engine before it makes a dent in the vast array of medical technologies.
Yes, these core technologies are important.
China should not get into a mindset where it needs to make *everything* itself. There are only a select number of core technologies it needs to master, there are many other areas where it would be better to source from abroad. The reality is, the best components are not always going to come from China, you never know when the smartest inventor or innovator in a certain area could be from Russia or Brazil or the Middle East or Southeast Asia. China should not be afraid to source from those areas to make its own products the best, while focusing only on core technologies that are the most difficult.
In an area like EUV, one reason why ASML beat out Nikon is that it's a highly distributed company that only makes a tiny portion of its components in-house, it outsourced most of the R&D to its foreign suppliers. Nikon on the other hand tried to do everything in-house. Thus ASML was able to take advantage of breakthroughs in other countries/companies, Nikon was not. China needs to be the same if it has a chance of ever catching up.
Let the US close itself off with one ban after another. China should position itself as an open and reliable counterparty willing to do business with anyone willing to do business with it.