How logical are Germany’s successes at the initial stage of World War II?

The whole point is that Germany at that time was the only state that used new or even modern tactics of warfare. Its opponents: England, France, Belgium, etc., used old techniques that were already ineffective. In this connection, there was a huge gap, which allowed the Germans to win big victories with small losses. The Second World War was already a mobile war, when tanks reigned on the battlefield. The Germans were able to understand this faster. We can say that their victories during this period of time were quite natural.