Actual design and building of physics experiments is a lot more complicated than “just doing it”. There are thousands of places that one small oversight will cause the entire project to fail. You will never successfully make a city size particle accelerator if you cannot demonstrate the ability to design and build a tabletop version, let alone a room scale, let alone a building scale, let alone a city block scale. It is cheap to demonstrate at a small scale. It is expensive to fail at a large scale.
With respect, I have no idea what your link has to do with anything. Making a giant dish is absolutely trivial compared to a particle accelerator.
My point is that Chinese medium-scale magnetic confinement fusion research devices have not learned from 60 years of painful lessons that the fusion research community have learned and published. Magnetic confinement fusion research machines share a lot of similarities to particle accelerators. Is there any indication that China would succeed in making a particle accelerator other than “they are good at STEM” and have made a giant parabola? It’s not very convincing.