Can you provide examples of it actually helping China?

Their supposed copycat jet fighter has gone nowhere so far. There's zero evidence they have the ability to bring it to production and deployment.

There are several countries that could build a 737 clone.

Cisco continues to dominate routers, despite China's attempt to steal from them and clone their products.

Windows, iOS, Android dominate operating systems, despite China's continued attempt to build a serious home-grown operating system.

Russia has been stealing US industrial and military secrets for 60 years. It also didn't do much for them. There is a lot more to it than just stealing trade secrets - that's the easy part.