Look up the Battles of Raseiniai and Brody to see how aggressive and often suicidal Soviet tank attacks were at the start of Barbarossa.
About the Pz IV F and F2, I stand corrected. It seems that the Pz IV G was produced in greater numbers and was the greater workhorse in the mid-war period. Thanks for forcing me to research my misconception and to correct it.
With regards to lend lease tanks your chances of surviving against Valentine VII’s would be better than against Shermans!
Cheers and good gaming.