At Versailles, Wilson intercedes and beats off French demands for revenge. Germany loses southern Sleswig, Posen (to the recreated Poland), and Alsace Lorraine. The Polish Corridor question is solved by creating a quadrilateral point permitting German access to Danzig and Polish access to Gdynia. Meanwhile, the Austria-Hungary Empire splits into Hungary, Galicia (which goes to Ukraine/USSR), southern Poland, Slovenia (which is turned into a buffer state as a compromise) and Yugoslavia. The remainder includes German Austria, Bohemia, and Moravia. As a face-saving measure, Germany is forbidden to Anschluss but isn't forbidden to form a customs and social union with Austria. Germany is required to pay relatively small reparations, far smaller than what French politicians demanded.
The result means there's no stab in the back myth in Germany, and Germans are grateful to Britain and the US for their support. By contrast, a stab in the back myth appears in France.
In the early 1920s, the Action Francaise stages a March on Paris and forms a fascist-like French government. Over then 1920s and 30s, there are similar fascist takeovers in Italy, Poland, Hungary, and Spain. The Irish Free State is also considered by many in Westminster to be drifting into the fascist bloc. In fact, virtually all predominately Catholic nations display signs of drifting into fascism.
In the mid-1930s, a crisis erupts over Austria, A Mussolini-backed fascist coup in Austria fails, causing bloodshed between German nationalists and fascists. A proxy civil war over Austria eventually spirals into an all-out war between Germany (now receiving substantial British and US aid) and the fascist bloc.
A lot of dead bodies later, Germany gains Austria, the Czech Lands (who didn't entirely enjoy fascist Catholic rule), the Alsatian-speaking part of Alsace-Lorraine, and some parts of Poland. It's also permitted to form a naval base on the Adriatic. Germany is now the undisputed hegemon of Europe, and while fascism has received a blow, it hasn't been killed as it was OTL.