What General Milley has been doing doesn't make logical sense.
His role is simply to advise the President and the DoD and he serves at the President's pleasure.
He has no operational authority to call China or do anything of that nature.
Trump did not remove him after he undermined him multiple times, Biden has not removed him after he called him a liar pretty much in testimony to Congress.
He appears to have some sort of omnipotent power that is unexplained. Or is he just a good actor? I don't know just asking questions.