There is a theory that the US loses every prolonged conflict by default, because taxpayers eventually lose interest in winning.
China is probably watching the latest developments in US support for Ukraine with great interest. If the support proves insufficient for Ukraine to win, they may conclude that there is no need for a proper invasion of Taiwan. That there is no need for an all-out war. They could just isolate the island, try to shoot down every plane and sink every ship, and take whatever casualties Americans are willing to take. If their navy and air force can match their US counterparts, they just need to spend more and last longer.