Maybe TSMC is not that important for making advanced weapons. It is still important for billion-dollar markets like cell phones, cloud servers, desktop and laptop computers, etc. For instance, Apple, which happens to somehow rack in money selling computing devices, is very dependent on TSMC, without a viable replacement available now.
Military hardware uses CPU technology that’s 10+ years old, of which the Chinese are capable of fabricating themselves on the mainland. The stuff needs to be rugged, and likely, radiation-proofed.
And besides, isn’t it easier for Switzerland to just launch missiles at the bridges, instead of actively maintaining explosive devices on each bridge?