They’re a globally important company but they’re not ASML and they’re stuck between two superpowers and the threat of potential total war. They’ve had the misfortune of being sucked into geopolitical maelstrom and those tides are far too strong for any company to resist.
Sure. Go home and make chips. Pass the tarrif costs on to customers. Would US customers have a choice?
So yes, US companies do have a choice. They can lobby Congress to cut off TSMC from their main hardware and parts supplier entirely, crippling it altogether, except for their Arizona plant which is ripe for nationalization for natsec.
For the cutting edge stuff TSMC is a monopoly.
So the EU offering something like nuclear weapons sharing à la that which Germany etc. would probably be reasonable if the US bullied Taiwan too hard. But I don't think it's happening, I think people want good relations with China.