No Russian civil war is easy. Just have the Kerensky faction tell the British that if they don't get some consumer goods and gold to prop up their government, they are going to make a separate peace.
The Germans deal directly with Kerensky instead of that traitor Kornilov. The Russians lose Poland, the Baltics, Finland, and Moldova. They spend 1917 and 1918 getting the farms back in shape and rehabilitating the railroads, then rejoin the war as the Germans are launching their final attack on France in the teeth of the American army.
The German retreat to the Rhine is outflanked when the allies pressure the Netherlands to join the war, followed by another entire American army unloading in Copenhagen and establishing a new front on Jutland.
Austria-Hungary collapses completely when the Hungarians change sides in the Christmas Betrayal of 1918, in return for the promise of not losing all their land in Transylvania to the Rumanians.
Germany's industrial wealth is essentially destroyed in the war. The first part of the war has an exchange rate of two to one in favor of Germany. The second part has an exchange rate of two to one against Germany due to the weight of American ammunition and aircraft. This is especially true for the period during and after the firebombing of Hamburg by the huge American Jutland front air fleets in July of 1920, after the American Liberty aircraft program gets into high gear.
The war ends in the smoldering ruins of Berlin in autumn 1920, as the Kaiser dies in his bunker with a gun in his hand.