it's true that there are energy deals between china and russia for natural gas, that's a completely different molecule and there isn't a good process for converting natural gas to the oil used in engines. there is also a deal to let china buy oil at a discounted prices but that isn't at a fixed point and it's still ultimately going to be subject to the same market pressures even if there is a buffer. oil is not delivered to end users through pipes but instead by ocean through freighters. this is not really that secure a shipment method - it just appears that way because the us has been (mostly) keeping waters safe for commerce since the cold war. the us has been pulling away from this role - reduced naval fleet and no more focused on giant ships. both foreign state action and piracy will present challenges secure shipping. this action from the us should spark some response from china and its been stockpiling resources but it's operationally stretched thin, relies on most of its inputs from sources outside of itself, and the us has allies in china's vicinity which hold us troops, tech and naval bases like japan. i agree it looks like we are approaching a now-or-never inflection point with china's ability to act on taiwan and its future as an expansionist power but china is much more dependent on the vast networks and institutions created by the us for trade and it knows it could be shut out like russia has been. it doesn't have the natural resources in needs to maintain it's standard of development on its own. it possibly wouldn't survive as a state if the same sanctions that were applied to russia were placed on it.
United States