WWI POD : Switzerland erupts in civil war over tension between the Entente-philiac Romands and Italians, and the CP-philiac Swiss Germans.
The Entente still wins WWI, resulting in a partition of Switzerland between Romandy, Deutschschweiz and Italy. It is to be noted most bicultural cantons were taken over by the Romance-speakers.
When Hitler comes to power, he doesn't have a place to stash gold in, but he has another country he can Anschluss easily. The Entente still gets another six months to rearm.
Romandy being an Entente member leads the French high command to decide to fight the Germans on the Rhine plains of Northern Switzerland. In consequence, they fortify more intensely the North of the country. They are completely taken short when the Germans invade in force the Low Countries, but the armies reinforcing arrive mostly in time. Sedan doesn't fall, and although the Low Countries have fallen, Maginot has held. Meanwhile, a Communist revolution explodes in Bulgaria, leading its neighbors to stage a short Balkan War to make sure it gets no silly ideas, grabbing border territories.
The Entente follows up on smacking Germany like a bitch until the German army has a meltdown. At which point the Romanians join the Entente over Hungary trying to grab Northern Transsylvania from them. Slovakia decides it was the real Czechoslovakia all along, and the Entente rolls on until the German-Soviet demarcation line. And forget the brakes.
The invasion of the Soviet Union entices many anti-communist powers to join the Entente, resulting in a one-sided beatdown for Soviet Russia, especially after the Japanese launch a massive offensive on their Far Eastern seaboard, cutting them off from any foreign supplies.
Five German states after the peace :
Suddeutsches Bund
Niederdeutschland
Königreich Preußen
Rhenisches Republik
and the best, Fürstentum Liechtenstein.
The Poles may have gotten a bit Kresy on the Intermarium idea.