I think this is an apples and oranges situation. China is not sanctioning or tariffing, they are banning exports of specific items for industries that their government is entirely in control of. The US can say tarrifs this and sanctions that but the private companies can do whatever they want, the US has no real power over them. China has unilateral control over these minerals and nearly every nation that trades with them has a strong incentive to not only follow whatever boundaries China sets for the minerals, but many of these nations are probably also happy to to comply because they don't have good relationships with the US either. If any one is middle manning them to the US, China is approving it, and I'd bet that if they say not to, it won't happen.

If anything I'd be worried about nations like Bolivia who also have some of these metals because the US could be more incentivized to destabilize them for mineral access.