I really doubt the U.S. will make war with China to defend Taiwan however tragic it sounds to say that. As of 2022 only 11 U.N. countries recognize Taiwan as an individual county?
Those countries are Belize, Eswatini, Guatemala, Haiti, Marshall Islands, Palau, Paraguay, Saint Kitts and Nevis, Saint Lucia, Saint Vincent and the Grenadines, Tuvalu and Vatican City. Not a single military power house in the bunch and if they ALL ganged up on China, their militaries would probably be obliterated in a day. Most especially since Russia, North Korea, and probably even Cuba would help China.
The USA once recognized Taiwan as a sovereign country but ended that in the Carter Administration.
I think there might be a huge outcry of FOUL if China invades Taiwan but I don't think there would be much financial or military assistance to Taiwan. The UN won't do much but protest with both China and Russia as permanent members of the UN Security Council and Russia has absolute veto power (one of the more stupid decisions that body ever made in my opinion.)
China stopped saber rattling against Taiwan when Trump was in office but they have no similar respect for Biden. I am pretty sure if Biden is re-elected, Taiwan will soon be no more than a province of China..