Maybe they are assembled in China?
You're not going to make money buying a new 14nm bitcoin miner, and that is where the China foundries are for cost effective silicon. They're great at 28nm+ and good at 22nm pricing.
Most new design modern sub 7nm ASICs are made in Taiwan/Korea by TSMC and SLSI. That is where miners are profitable.
Whatever speculation you have on China’s foundry capabilities or a gap to TSMC will be wildly out of date within a year or 2. I’ll bet on it.