Saudi Arabia oil exports are 200B USD/year, give or take. The world has a GDP of ~100T USD, how much of that is traded in US dollars? We could put an estimate based on total currency reserves, of which USD is about half of that. 200B out of 50T is "merely" 0.05% ...
Sure, they may be one of the single major traders of USD, but at 0.05% what this tells you is that the USD is extremely diversified, and that's good!
(Also, this is implying Saudi Arabia bins the whole deal overnight, which is very unlikely to happen)