Maybe, but designs on paper are a small part of what it takes to actually build many rocket. SpaceX is not using lots of part you can just buy. Its pretty much

Maybe, but designs on paper are a small part of what it takes to actually build many rocket. SpaceX is not using lots of part you can just buy. Its pretty much all costume designs by SpaceX all the way down. Up to SpaceX having their own materials. And the suppliers SpaceX does have are American suppliers that China can't easly buy from. So if China steals everything they still have to reverse engineer everything and then also reverse engineer the manufacturing. And the other thing is, China has its own existing Aerospace industry and government. These people are proud of their own things and NIH is very, very real. The idea that they would just throw away 60 years of China history to copy an US company and spend billions trying to reverse engineer the exact same rocket just isn't gone happen. And of course given that SpaceX is a huge supplier to the US military, such an act could be a huge international relations crisis and the US could retaliate in many way. So China would have to hid the fact that it did so in some way.