Another problem (which Trump is idiotically pushing) is for everyone else to grow their military. Do we really think the world is safer with more countries having larger militaries that are an election or coup away from no longer being allies?
Ie China is not doing sudden backstabbing of its allies, strongarming weak at their weakest point. In contrary ie it helped develop parts of Africa that were severely neglected by western powers, not for free but that was never the case. They did some not so nice stuff, but so did US in the past, in much higher numbers. Tens of millions of civilians are dead because of failed US policies and invasions which ended in withdrawals and defeats in past 80 years.
With all negative stuff on China (uighur treatment, other cases of human rights violations) its still shines compared to US now. Now for any outsider (>95% of mankind), why should they still ally with US now?
China seems a lot more reliable than the US, and has seem more reliable for quite a while.
You speak as if the US does not exploit others dry. The US is a lot more malignant than you make it sound.
If America was suddenly no longer a hegemon, it would be qualitatively different. There are other hegemons in the world that would step into the void left by the U.S., and it would be their influence that would be felt most the world over, including by the countries you named.