US does not have expertise to make modern non-nuclear subs. China can intimidate anyone in Europe not to sell. It was fortunate for Taiwan that Chinese pissed off Japan enough. Half a dozen of Soryu knockoffs can shut down PRC maritime trade if needed.
Biden has to repair our US hegemony. Trump sure hurt it a lot in spite of his anti-china rehtoric.
Selling weapons to taiwan doesn't contain china. We will send our own guns if a hot war is brewing there.
Taiwan recognition is not the same thing as meaningfully containing china. The TPP and asia pivot from obama was the last time that america seriously tried to restrain the rise of china.
All of these states need to be strong enough to be a credible deterrent to invasion on their own.
US support is neither speedy nor certain. And a speedy capitulation by Taiwan compromises the US's ability to help even if willing.
Trade deals are ugly.
But if your geopolitical goal is to prevent Asia from moving closer to China, you can, and we have, done worse than the TPP.
And people still celebrate Trump for being tough on China...