ASML literally makes the most complex machines on Earth. Sure rockets are powerful and they help us reach outer space ... yet they need computers to do so. Computers in turn are made with lithography machines and the SOTA is ASML.

Also ASML is not alone. In fact ASML can not exists without its partners, first and foremost American Department of Energy but also s IMEC in Belgium and Zeiss in Germany. Those are all SOTA in either R&D or production. They are not "some of the best" they are literally the best in their very complex expertise. In fact they have to collaborate reach such level.

... and yet, it's "just" that. There is nothing magical about ASML. Yes it might be practically impossible because of IP, economics, etc but still China (or anyone else) can definitely pour a lot of resources to try and make significant process. Will the result be competitive though in light of the moat ASML has, in particular partnerships, that is hard to imagine.

PS edit : I did like Chris Miller's "Chip War: The Fight for the World's Most Critical Technology" and FWIW did have a former colleague working at ASML and been invited to IMEC events.