Samsung has just as many ties with the US as TSMC. Both companies use semiconductor manufacturing equipment from US firms like Applied Materials and KLA. The reinterpretation of US export controls that bars TSMC from selling to Huawei extends from not just barring companies from selling products to China with US technology inside, but also barring companies from using US technology to manufacture Chinese-designed products that are then sold to China. This applies to Samsung just as much as TSMC.

TSMC isn't real bottleneck here. It's US semiconductor manufacturing equipment firms fully under US jurisdiction that underpin the supply chain for any modern fab.

this area of industry is perhaps the most interesting- the firms doing research and at the forefront of chipmanufacture, but in the lay tech press doesn't get a lot of fanfare. Are there good links to write-ups about how this industry is structured, etc? The only other company I know about is ASML who makes the EUV lithography machines...

https://semiwiki.com/ has a lot of cool stuff on the semiconductor side.

https://www.nextplatform.com/category/hyperscale/ has interesting stuff on uses and development you don't see from a consumer POV

I would add lithoguru.vom and the related courses (Chris Mack) as well as semiengineering.com