Why did the USSR fail at the beginning of the Great Patriotic War?

Indeed, at the beginning of the Great Patriotic War, the USSR suffered setbacks. They were caused by the fact that;
1) Germany’s military advantage at the start of the war was obvious;
2) Germany’s attack on the USSR was sudden and unexpected (Stalin did not believe that Hitler would be able to strike without appropriate preparation);
3) Units of the Red Army that did not expect a blow and were not ready for defense.
All three of these factors together ensured the initial success of the aggressor invaders.