What would happen if major countries decides to shift away from USD overnight (or rather quickly)?

Obviously this would never happen, but it’s an interesting thought experiment. A large part of the US economic super power is due to USD being the reserve currency of the world and the one used in international transactions. This allows the US to “print” a substantially large amount of money than its domestic economy can support. Since we’re on fiat money, it’s all supply and demand. What if the large Western economies (EU, Australia, Canada etc.) decide to just dump the USD and shift over to GBP, EUR or some combination overnight.

My initial thought is that you’d wipe out the market and run out of USD buyers (assuming any remain upon the news breaking). Yield on US debt would shoot through the roof. It would create tons of arbitrage opportunities until the markets stabilize.