It doesn't change the physical realities of that much at all besides maybe slightly further cementing that the US will not come to Taiwan's aid.
No, the main change is that now Xi can more reliably expect a weaker, less unified response from the west due to political divisions inside America as well as between western nations. He can expect less diplomatic pushback, fewer sanctions, etc.
Also, no all serious leaders do not only respect power. Serious leaders who are also morally and ethically good also take into account right and wrong when they make decisions.
The right thing to do would be for America to try to preserve and enforce a rules based order, regardless if other countries do. America has significant agency in the world and should consider how the world should be and try to get there. Not only consider how the world is.
