It's AI vs AI balance. It always strange why USSR often got beat so easy by Germany.
Mmmh, I am not sure how to express it without it somehow sounding weird but I think it shows how dangerous, how desperate the situation was for the USSR.
In the very first 6 month more Red Army soldiers died or became prisoners of war than the whole Wehrmacht counted soldiers. More tanks got destroyed, more planes than Germany possessed. The Red Army was shattered, severly defeated and the enemy standing near Moscow.
On the German side: One might think, in such a situation, after a near ideal development of the war and all this victories, everything would be fine... but it wasn't. The whole war had been a wager on defeating the Red Army severly enough that the Sovietunion would either give up or crumble... it did not.
The highly victorious Wehrmacht, at the end of the year 1941, was completly used up, stressed, not able to replace wounded and dead, bonedeep exhausted and so far beyond working logistic lines that the Generals had to chose 2 out of 3: oil, munition or winter clothing.
And there was no plan B. No plan what to do if the Sovietunion, so heavily defeated, would not give up but just kept on furiously fighting. And not only willing to keep fighting but also able to.
This the situation when the first snow began to fall in the war, the first winter of Великая Отечественная война Welikaja Otetschestwennaja woina. And the Red Army, strenghtened by divisions from the far East Asian border, went into the winter offense of 1941/42 and then the feared Wehrmacht, slowly freezing to death, nearly got completly defeated and was close to falling apart (but in the Russian winter in your summer uniform... how and where to could you run away?).
Neither did the USSR crumble within the first 6 month of 1941 nor the Wehrmacht in that horrible first winter 1941/42, the war raged on for more than another 3 years.
And to answere your question or complaint:
It's not easy to simulate this situation with a few scripts on a computer.
There are usual 2 complaints: Why is the USSR so easily defeated? Why is it impossible to defeat the USSR?