What was the turning point of World War 2?
Battles like Stalingrad or El Alamein ended in significant large scale losses that in a view of the overall war were turning points.
We often don't know turning points in a war until its over. World War 2 has been analysed extensively and there can be differing opinions about actual turning points.
Strategic battles often have territorial losses but there is also material and human losses that can make a difference. The loss of experienced naval pilots by Japan at Midway greatly affected their ability to fight in the air. The loss of their large Aircraft carriers greatly affected the Japanese ability to carry the war to their enemy.
This was a turning point because Japan went from being on the offensive in the Pacific to being on the Defensive.
Great numbers of causalities at Stalingrad and the aftermath of the Case Blue Offensive greatly affected German morale and capability. This was a turning point because the German could no longer threaten to destroy the Soviet Union. Germany would be steadily pushed back after the crushing defeat at Stalingrad.
The shattering of the German Army Group Center in 1944 that was a result of Russia Operation Bagration was a big Strategic win in Russia.
The battle at El Alamein ended the Africa Korps last chance to win a decisive victory in North Africa. The Germans would retreat from this point on until their final surrender in North Africa.
Long term battles like the battle of the Atlantic can have turning points. New weapons and aircraft in 1943 made the Battle winable for British. Allied ship losses began to fall in response.