* https://www.washingtonpost.com/national-security/china-hyper...
* https://www.washingtonpost.com/national-security/biden-admin...
The TL;DR is that one of the sanctioned companies, Phytium, designs chips used in a Chinese supercomputer that the PLA's researchers use to simulate hypersonic weapons. The chips are designed using tools from Cadence and Synopsys (both American companies) and fabricated at TSMC.