Can you point to anything to suggest that the state that has successfully overthrown dozens of nations and has a “Tibetan Government-in-Exile” just waiting to take over wouldn’t be able to do so?

Because the US is not omnipotent, and more often than not, it completely falls flat on it's face?

The US has completely failed to pacify a nation that borders Tibet, that is both much smaller and less mountainous. A country that borders China had a very long war for it's independence, in which the US was actively involved for 10 years, and during that war it also ended up having to fight china itself. Falling to western imperialism is not inevitable, and any attempt to pretend otherwise it really just an attempt to legitimize chinese imperialism.

And, again, equivocating between the US and China is absurd.

Fundamentally, I think this where we're at an impasse. I think they absolutely are equivocal, both fundamentally being bourgeois states seeking to increase their power through imperialism - the only difference being danger - China is less dangerous to most of the world than the US, but to the Uyghur and Tibet, absolutely not.