China has been producing ARM chips like the A20, H40 (raspberry pi class competitors, dual and quad core SOC; went in to a lot of low end 720p tablets in the early 2010s) for a while now, their semiconductor industry is not zero. The biden administration turning off the chip supply in 2022 was nearly 3 years ago; three years is not nothing, especially with existing industry, and virtually limitless resources to focus on it. Probably more R&D capacity will be coming online here in the next year or two as the first crop of post-export control grads start entering the workforce in China.