Does TSMC and Taiwan in general do much business at all with Mainland China? I would think, especially given recent geopolitical events and the significantly more concerning saber rattling by the PRC would preclude Taiwan giving the mainland anything really meaningful in terms of tech. AFAIK these new chips are coming out of SMIC, not TSMC, and considering it’s the PRC, it’s very possible that significant portions of the architecture were just reverse engineered.
If there was any confidence this is a homegrown design, I'd agree. But in all likelihood, they've just reverse engineered and copied Intel architecture and claimed it's their own.