Sorry but I'm not American so this whole whataboutism game doesn't really work on me. I actually think America are in fact the worse of the two when it comes to international activities and by a wide margin. I also do in fact boycott American companies based on their profiteering and support for both the Iraq War and the illegal Israeli settlements. I pretty much avoid all products from the UAE and Saudi Arabia as well for similar reasons. This is a fake dichotomy. I can condemn both China and America because I don't see them as that fundamentally different.

Both are capitalistic societies - one with neoliberal leanings and the other with a totalitarian state controlled capitalism. Both are intensely hierarchical and class based societies and neither are democratic to a meaningful capacity.

Organisations that derive their stability from a base of exploitation do not deserve to exist and I frankly care more about the plight of the workers in the global south than people being laid off in America or China (which is already beginning to outsource work to African states the same way the US had started to outsource work to China). That's not to say that their plight does not matter but keep in mind that much of the material wealth and stability that the US (and to a lesser extent, China) and even it's working class citizens enjoy was built off the back of the South.

I am in agreement that boycotts on their own are largely symbolic gestures but broader economic sanctions do have a history of working, South Africa being the most recent example.