Saudi Arabia selling cheap oil is a central pillar for the modern industrialized nations in the global north. East Asia and Europe will be most heavily affected. Fancy cars, trucks and planes become worthless without oil to power them.

Given the circumstances China will team up with Saudi-Arabia and Pakistan against the Houthi (China already sells drones to Saudis). Europe might also start its own mission against the Houthi with Saudi-Arabia and the US.

The US might profit from high oil prices, as Saudi Arabia will be one less competitor. In the short term they might stop Diesel exports because of internal shortages, if there is some will to stabilize internal politics remains.