If the two sides don't make trouble, they should not be able to fight. But the attitudes and goals of the two sides in the fight are different. The goal of athletes is to win the game, while the goal of soldiers is to kill the opponent to gain a chance of survival. From this perspective, athletes should not be able to defeat soldiers.
As for the German army in World War II, the fighting ability should not be bad. Compared with the Eastern army, Europeans and Americans have an advantage in physical strength. But their fighting skills may be inferior to those of Easterners, and their flexibility may also be inferior. But I personally believe that fighting on the battlefield depends on a person's physical strength, skills, fighting will, and desire to survive. We cannot simply say how good an army's fighting ability is. After all, fighting is an individual matter.