Too many people are conflating too much here. The initial OP is that sometime in the spring 1919 the Germans decide to basically kick Versailles to the curb and restart fighting to grab some land in the east/prevent some territorial concessions. Unless I am missing something, this means from November 1918, until the spring/summer 1919 everything has gone as OTL. This means the squirreling away of armaments is at the same level as OTL, the production of ammunition of all sorts has basically been halted, and production lines shut down, crews of ships not sent to Scapa or elsewhere reduced to minimal levels, pilot training ceased and the mechanics who maintained the aircraft back in civilian life. As I have posted before, those other members of the alliance are bust collapsing and have internal problems that make German problems look like nothing. Don't forget that, by spring 1919, most of the remaining armed forces under central control (Freikorps don't count) are units that have been put together out of other units so cohesion, even with trained veterans, is not what you'd like it to be and often officers and NCOs who have not worked or trained as a unit very much - which impacts unit effectiveness even with veteran troops.
If you accept that "war-weariness" and collapse of the home front was the most important factor in the German surrender in 1918, you are then arguing strongly against guerilla war. If you don't have strong support amongst the civilian population for an insurgency, it will collapse pretty quickly. Even with civilian support, the sea for the fish of the insurgency to swim in, this wear is not always won by the insurgents. I ave no doubt that had there been some sort of uprising in German cities the allies would have certainly cut off food supplies, and if the urban fighting was significant simply unleashing the artillery on a city - after all outside of the Rhineland (which they already occupied), and parts of the Ruhr, which they might wish to exploit, it matters little to them if Heidelberg or Berlin is reduced to a sea of rubble.
In any case the German Army was retreating to defensive lines further back in 1918, even with the stoppage of fighting in the east and the troops moving west, not because it was winning or even staying even. It was losing, period. This is not an evaluation of whether or not the German Army was better than the Allied armies, it is the reality that it was exhausted, outnumbered and out produced in military materiel. These are factors that, even if you say the Germans were qualitatively better, could not be overcome. IMHO if you think Versailles was vindictive, if the Germans had fought in to 1919, which would have meant a huge increase in US casualties, any moderating influence Wilson might have had would have been unsupportable domestically. In 1919 Germany had been a united country for 49 years and there is no reason that this could not and would not have been undone by an allied coalition that fought their way in to Germany, even to Berlin.
I believe it was a GERMAN military theorist from the 19th centuries who talked about centers of gravity and the national will to fight - the military might of a nation was a continium with no real front or back so if there is no back there is no Dolchstoß.