It was catastrophic to the intent of the German idea of quick victory because it didn’t allow the maximum clear weather. With those 6 weeks, Moscow would have been taken, severing north and south axis of communication and supply because all the rail lines tied the Soviet logistical support were centered along Leningrad, Moscow, Stalingrad and Caucasus.
The Soviets were running out of space to retreat once they left Moscow. Germany only had to cut the rail lines that tied Tankograd and the Ural industries to the eastern portion behind Moscow and they could not supply the front.
But the Germans wasted a whole year from June 40-41 basically doing nothing and should have gone after the middle east and British supply flowing in the Medd by taking Malta, Suez and Gibraltar. Then used the Italian fleet to seal up the medd
That would have made Turkey more friendly to Germany and possibly allowed Germans to pass into black sea. Turkey could have been bought off to fight the Soviets because they are old enemies because the Russians supported the Armenians to raise up against the Ottomans and fight the turks and Turkey never forgot that.
With Turkey in the bag, pressure could have been exerted against Persia and cut the lend lease route. All this was possible in that ‘lost’ year.
The Germans basically had enough to win the war in 1941, but mismanaged the campaign and the timetable.