Also, the US must know that it cannot win in any conflict with China regarding Taiwan right?
Taiwan is idealogical to China. Taiwan is merely a pawn in the game for the US. The US will bow out of a war for Taiwan within years but China will never give up - even if the war lasts 100 years.
Lee Kuan Yew (first Singapore PM) said it best: https://youtu.be/q_gr3dtBaic?t=682
Therefore, it's in everyone's best interest to maintain status quo and not to disturb the delicate balance of China/Taiwan/US. The Obama administration got it right. The Trump and Biden administrations have not. Nancy Pelosi flying to Taiwan looks great for her career, but terrible for everyone else.