The German effort collapsed because the Kaiserschlacht failed, seen as the last desperate try (which it was) - Driven less by strategy, (apart from the strategic consideration that they had to act before the US got there in Force) and more of a desperate gamble, in many ways way to reminiscent of the Eastern front (where due to the size of the fronts the rules were different) to ever really work.
That being said, With No US troops, because the US isn't in the war - There wouldn't be any strategic need to win right there and then.
Either the strategy is just straight up trying for peace, so no offensives, just telling the French we are willing to leave as soon as you make peace or make us, Or, a decisive offensive like Kaiserschlacht but under no particular stress (say by hitting the vulnerable logistics of the BEF that was ruled out OTL due to the timing). Another option is a limited offensive in France to rally morale, but not some sort of war winning offensive, or, maybe a peripheral strategy say in Italy.
It's also worth noting that just by delaying the end of the war a few more months more facts would be made on the ground in the east that would be hard to unmake, especially with no US seat at the table.
Lets say it's a loss though, it wouldn't be the take it or leave it ultimatum that was Versailles, because absent US manpower it's unlikely the Germans would have felt quite as outnumbered as they did OTL. Certain of their defeat yes, but it would still be a negotiation. That would make it harder to paint as the stab in the back - not impossible, but much harder. This is especially the case if say Austria and the Sudeten are incorporated and the Poles told to be lucky they are back as an independent nation.
In that case you could make the argument that the 'traitors' made a bad deal, and lost the war instead of winning it, but ITTL, the loss would be money and AL, and the gains significant. That peace treaty could be defended as maybe getting out early instead of toughening it out, but saying that Germany couldn't take another winter.