I disagree, Hitler had no choice to strike Russia when he did, in fact, he wanted to do it earlier, but the Italians screwed up in the Balkans, and he had to bail them out.
Russia was only getting stronger with each day, and the window for successfully attacking Russia was quickly closing. In fact, Stalin had every intention of striking against Hitler by 1943.
Hitler’s mistake was not taking a “divide and conquer” approach, Stalin was so hated, that many would have supported the Germans, especially the Ukrainians. The Germans could have basically allowed Ukraine to be a “puppet state” much in the way Slovakia was.
IIRC, the British knew Barbarosa was coming and fed false intel to the Germans about invading Greece for the sole purpose of delaying the Russian invasion. The two month delay worked better than expected.