At 4.40 you made a big mistake the Self propelled guns mentione SU and ISU was placed on the KV and IS series of hulls. The T34 SP versions was the SU85, SU100 and SU122 versions.
We must acknowledge the British for developing the first tanks during World War I. The Germans later significantly improved upon this technology, creating some of the most advanced tanks and weaponry by the time of World War II. Although Britain's naval force remained superior, Germany's military equipment and soldiers were among the best in the world during that period. Germany had been preparing for the war for many years, almost immediately after the end of World War I. The Treaty of Versailles, which followed the first war, imposed harsh conditions on Germany, fueling resentment. While the UK and other global powers initially sought diplomacy with Hitler, his overambition led to further conflict.