Funny thing to mention, I think 95% of industrial espionage effort yields zero if not negative benefit. The problem is that you are always stealing a "cat in a bag"
For machinery, rarely there is anything like a "secret sauce:" Soon after the fall of USSR, Chinese defence companies flocked to Russia buying every defence tech possible. Russian companies had a funny way to troll Chicoms: they will not sell them a simple, mid-tier equipment, but only the top notch, and most complicated one, with which even they themselves had problem dealing.
For example, Soyuz transferred tech for their super expensive, small volume manufactured R179 engine. Yes, that was Soviet response to F135 class engines. The showstopper was its very high temperature turbine made with monocrystaline blades grown in situ within (!) a ceramic fibre reinforcing mesh.
Even with all blueprints, documentation of manufacturing processes, and working samples on their hands, Chinese never made a single working engine. That state program to copy R179 continues to this day as I know.
And I think they spent way more money on it in 25 years, than if they were to create a thing from scratch. That is something obvious to every experienced engineer, but not to bureaucrats from Chinese three letter agencies who are convinced that they are just an inch away from some "secret trick" that will magically make everything work.