Disruptions would be there for sure. But I think building up that kind of capability is necessarily single-use only, and only makes sense if your goal is to use it as a direct prelude to an invasion of a country. Because people will relatively quickly discover where the problems came from, punish whoever's responsible and then switch manufacturers. I don't see how this could be of benefit to secret services whether from China or any other country, except in the worst case stated above. A few billions in economic losses due to stock market disruptive etc dont mean much in the grand scale of things (and can't therefore be very attractive for intelligence services). Military planners would be foolish to outright dismiss this possibility, sure, but I don't think us-China relations are at this point yet. (And hopefully never will.)
The solution to all of this is to work together and increase the security of the overall system and ditch security through obscurity and security through NDA, go open-source and full inspectability for all critical infrastructure, be it comms, industrial controls, medical infrastructure, transport etc. And E2E encrypt all communications. Everything else is just screwing around with the symptoms instead of addressing the root causes.