Most of the rest of the world can buy Nvidia if they want to. And I don't think the EV comparison works, since China already had a large domestic market and established ICE car companies who could afford to electrify some of their lineup and slowly gain market share this way.

That is not at all the case. Biden export controls for nvida chips are still in place. China also has a large domestic market for chips. The rest of the world would gladly buy competitive Chinese chips.