If we consider 1937 as the most unclear phase of World War II, then 1938 was the most brutal year.
This is not without proof. In the first half of January 1938, the Britain-France-Australia trio successively launched the North Africa offensive, a grand counterattack in France, and the Normandy landings, involving millions of soldiers across three battlefields, and employing countless airplanes and tanks.
To counter the successive pressures from Britain, France, and Australia, Germany could only continuously mobilize new soldiers domestically, who, after hasty training, were thrown into the French Battlefield.
The war did not cease in Eastern Europe either. On January 22, 1938, amid heated battles on the French Battlefield, the Germans urgently commenced the Battle of Stalingrad.
According to the German Chancellor's own words, they needed to capture all of Stalingrad within six months, then push towards the Caucasus Region to cut off Russia Nation's energy supply.