Ptychographic X-ray laminography has come a long way and can image even the latest chips at the transistor level:
https://spectrum.ieee.org/xray-tech-lays-chip-secrets-bare
True, it requires a synchrotron (one of the few things that actually costs more than a chip fab), but China has those:
https://en.wikipedia.org/wiki/Shanghai_Synchrotron_Radiation...
China might not be able to make bleeding-edge 2nm chips, but it has the equipment needed to expose any backdoors in them. Publicly, worldwide, with proof. That is an existential threat to any hardware manufacturer -- getting caught doing that is a bankruptcy-level event. Until recently they didn't have to be afraid of getting caught.
Being able to image chips at the gate level or better is a critical lever in fixing the balance of power between hardware manufacturers and their customers. It's why Bunnie Huang's work on IRIS is so important: