If physical delivery is allowed, the exchange will gradually increase the deposit, which can generally reach about 30%, and then it must deliver or receive the goods. If the goods are not delivered or received, the exchange will impose penalties.
The buyer and seller of futures contracts are one-to-one. If retail investors are forced to close their positions, they will definitely find rivals. If they can't find it for the time being, the price will change until someone accepts the closing orders of retail investors.