I can only speak for my own experience, I’m lousy at micro management in the game. Unfortunately a degree of micro is necessary for Barbarossa, and that is of the mobile divisions.
My initial offensive didn’t go well compared to historical; however made a massive pocket at Kiev , once this pocket collapsed the Soviet Union began a trajectory of continuous decline. Afterwards I had three army groups on the front, which with the current game mechanics is a real mess. Would occasionally have to readjust the frontlines.
Initially I would not attack with my infantry which was all 10 Inf 20W with support ENGR and ART. Once pockets were sealed would attack. After Leningrad had fallen I attacked across the entire front including with my infantry Moscow fell then Stalingrad. Even attacked through the winter. Since logistics are not really modeled in the game did not have supply issues. I did make a big investment in infrastructure 100% to East Prussia and Lublin. So had a pathway for supply under current mechanics.
The greatest factor was that I followed Porta80’s video on the initial build. As a result all of the armored units were level 2 mediums and this was the decisive factor. I don’t think the AI even had T34s.