I feel like it’s the similar to their opposition to Russia. These powers are growing their influence in regions where the US used to have free reign, and there is so much operating on that condition that having it be disturbed feels like an existential threat to a wide array of interests. American hegemony is financially beneficial to a lot of people. A multi-polar world would also strip the US State of much of its “freedom of operation”. Looking at the Endless Frontier Act for example, I think it’s motivated by the anxiety about China’s chip production and how it could be leveraged against the US in a dispute with China. It’s harder to do things like the Iraq War if doing so sparks retaliation from other countries that have the political independence and economic/military power to do so.