Of course Biden won’t intervene. China owns the Biden’s.
I have a general comment to make.
I’m not really talking about Taiwan.
I’m not really talking about relative strengths of the US military vs Chinese military.
China owns a lot of our politicians, basically all of our media, and some of our military leadership. If we ever got into a hot war with China (over Taiwan, India, or any other topic) we would, to say the least, be fighting with one arm tied behind our back. Powerful American forces would be working hard to make sure we lost the war.