Here's a thought experiment. What if the country we now call Belgium had instead been partitioned in the 19th century with Holland getting Flanders and France getting Wallonia? Assuming that doesn't butterfly anything else, the French would build their Maginot line along the now extended border with Germany. So when Hitler invades, he would have to go through the Netherlands. Would this slow down the Wehrmacht and perhaps prevent the fall of France?
Impossible to say. It would change simply too much. For example, you are giving France a large amount of coal fields. That alone would change the balance enough (larger population, richer, longer borders with Germany) that France might be equal to Germany during the Franco-Prussian war and beat the Germans or fight them to a standstill. It would certainly change WWI. No Belgium would mean a very different reaction from Britain during WWI. Would they still join? Would Germany still be as succesfull without the Moltke-Schlieffenplan (or whatever it wascalled)?
Those are simple and obvious butterflies. there are a lot of smaller one, like the Luxemburgcrisis, the Scramble for Africa, etc.
Simply put, you can't simply ignore the butterflies. If you want to do it, that's fine. But in that case I think you better ask the same question at the ASB forum, because I fear you need them. A better question though would be ignoring ignoring Hirler and the Nazi's and simply assume a similar situation in middle 20th century Europe. So Belgium is partitioned between the Netherlands and France. Germany still unifies and has a dictator around the middleof the 20th century who wants to attack France, while technological progress is similar to OTL. What would happen to his attack on France. In this way you ask basicly the same thing, while still not ignoring crucial butterflies.