The very same people who are upset that Apple is dragging their feet over implementing the demands of the DMA in the EU are probably also the same people who are upset that he isn't doing more to oppose the incumbent US government.
In the former, opening up iOS and allowing developers to skirt around the App Store would not be in Apple's financial interests, given how lucrative the Apple ecosystem is, and how much money is transacted in the App Store every day. It therefore makes sense to me that Tim Cook would want to resist caving in for as long as possible, or at least until he figures out how to capitulate while giving up as little as possible, profits and control-wise.
In the latter, you either oppose Trump and be slapped with hefty tariffs, or you stay on his good side, and maybe even get his help to try and fight the DMA in some manner.
pluralistic.net
I don't live in the US, though I understand that Tim Cook does not exist to fight anybody's political battles for them. If you are hoping that any new CEO at Apple would have a change in approach, I wouldn't hold my breath. At best, he's a product guy that doubles down on making the familiar hardware that you all knew and loved while fixing the software bugs, but I don't see any new direction in terms of dealing with global political issues.