I did read some articles recently which studied the state of German forces in the east prior to, during, and after the outbreak of the revolution in Germany and it was pretty interesting. I’ll have to find it, but IIRC it showed that even in the months prior to the Armistice, many German formations in places like Ukraine and the Baltic were in the process of disintegration due to local pressures, partisan attacks (especially in Ukraine’s eastern frontier, where garrisons were in isolated blockhouses which could easily be wiped out), fraternization with socialist agitators, desertion, etc. Thought this was an interesting point to trot out the next time someone discusses a post-1918 German intervention in Russia against the Bolsheviks.
But basically my common answer to these threads is always the following set of events: Germany secures a favorable armistice in the West and the social deterioration in Germany is so bad that they must demobilize and attempt to resume food imports. Despite the dreams of German high command, an attack against the Bolsheviks is not viable. Some number of German troops are kept active in the east fighting local insurgents, of which there are many, especially in Ukraine. The post-war orders there slowly stabilize, but remain difficult. Some German political factions are interested in aiding the whites, but the intransigence of groups like the Volunteer Army over “One Russia indivisible” and Great War loyalties creates major issues. After military victories on all fronts, the Bolsheviks prevail in the Civil War in the early 1920s. Periods of calm (and Soviet attempts to secure trade deals) and interspersed with tense moments over Comintern activity in the eastern satellites. History ensues.