I concur with
@FillyofDelphi . And there's a logical Problem here. The war Economy of the CP will only last into 1920 If boosted by Ukrainian Imports. Ukrainian imports require meddling in the East, though, for which the CP have no power to spare If they want to bleed the Entente white in the West (which is the only way war lasts into 1920).
May I suggest Victory in 1918 instead? Germans capturing Hazebrouck and the coal mines of Bethune with a better Operation George, driving a wedge between British and French forces and cutting off Entente rail supply to the Front? If the Germans capitalise on their Advantages wisely, they can soon catch Amiens and/or throw the BEF back on the Channel ports. With No hope of American aid saving the day,
there might be revolution in France, or Britain abandons Belgium and France in Order to hammer Out an Ok Deal for then regarding Arabia, Mesopotamia and Africa.
Not exactly super-likely either. Germany now struggles to chew what they've bitten off, but that certainly entails keeping the Ukraine outside of Moscow's spüre.