It's not a huge problem for China those kill switches, but it's most definitely a ball twister for TSMC. The US can pretty much go build some factories in Arizona TSMC and Samsung, if not it would be a shame if those EUV devices somehow stopped working.
It wouldn't be a problem for us at all. When China reunites Taiwan, the euphoria will be so great, nobody will remember or care about those EUVs in TSMC and that's
if they are even still competitive, which they may very well no longer be in the coming decades with the rise of Chinese lithography. We take Taiwan for the Taiwan, not for the EUV lithographs. The only reason this is even being talked about is because all Taiwan is worth to the US is semiconductor technology so they're buggin' out trying to protect that while the Chinese are looking at the people and the cities. To the Chinese, reunification is life.
On the other hand, it would be a fun hackathon challenge to see if we can trip those kill switches at random times to f with TSMC at random times just for fun!