Building on what others have said might I ask what your POD is? I don’t think an end to the Western War after disaster at Dunkirk is impossible but I think it might be worth doing further reading into German tactics and strategy as well as Anglo-French counter-strategies. In my experience after doing reading on these subjects PODs and ideas suggest themselves.
Well, it's a story I've been working on for the Alternative History Wiki in Spanish (I'm Spanish, so I apologize if my English is very bad) since I was 18 years old.
At first it was completely full of clichés (super-technological Germany, Hitler changes his mind based on ASB, the German generals were all good strategists, the Soviets and Americans only won by numerical superiority, etc...) but as the passing of the years and delving into both historiographic readings and well-constructed alternative histories (especially like the ones in this forum), I polished it the best I know how to make it as realistic and rational as possible.
After years of collecting World War II information from OTL and other more realistic alternative histories of an Axis victory, I have come to the conclusion that any PoD after the failure of Operation Barbarossa can lead to nothing more than reproducing a different version of OLT (that is, unconditional surrender of the Axis Powers) or a peace agreement that leads only to a status quo ante bellum, which would then be reproducing a world quite similar to ours only with a better standing Germany.
In addition, since the Second World War is such a complex event, a single PoD is not enough for everything to go well for the Axis, but I have opted for a Butterfly Effect by which a series of PoDs is triggered that I consider necessary for the Axis, which already started from a bad enough material and strategic situation to win a war of attrition like World War II, at least achieves its most realistic objectives. These P0D, in general terms and summarizing a lot, are the following:
1.- 1932: Japan discovers the oil fields of Daqing and Liaohe (Manchuria). This will lead to a greater motorization of the Imperial Japanese Army and a strengthening of its influence against that of the Imperial Navy, triumphing over the idea of Hokushin-ron (北進論, "Northern Expansion Doctrine" or "Northern Way") against the Nanshin-ron (南進論, "Southern Expansion Doctrine") of the Navy.
2.- 1933: Franklin D. Roosevelt is assassinated by Giuseppe Zangara.
3.- 1936: During the Xi'an Incident, Chiang Kai-shek is assassinated.
4.- 1937: The Marco Polo Bridge Incident does not occur, so the Second Sino-Japanese War does not break out.
5.- 1939: The Nomonhan incident or Battle of Jaljin Gol (which is won by the Japanese) triggers a Second Russo-Japanese War or Soviet-Japanese War.
6.- 1939: Winston Churchill dies when HMS Nelson is sunk by U-56.
7.- 1940: During the French Campaign, there was no break in the siege of Dunkirk, for which the German victory was even more complete and crushing by capturing all the French troops and almost all of the BEF.
8.- 1941: Due to the Dunkirk debacle, the entry of Spain into the war and the lack of military successes (absence of Operation Compass in Egypt, along with the seizure of Gibraltar by Spanish-German forces), Great Britain signs peace with the Axis powers in the face of generous German offers and US disinterest in entering the war.
Thanks for answering.