The Eastern Front was very much a game of leap-frog technologically as much of Russia, while brutal on tanks, was very much suitable for tank combat.

In the early stages of the war during Barbarossa, Soviets had a relatively large technological jump in the Germans. The Pz. IV's and StuG III's armed with only the short KwK 36 75mm were completely inadequate at engaging T-34's beyond knife fight range and were completely helpless against the KV's. The primary anti-armor tank of Germany, the Pz. III with the KwK 39 was also unable to properly engage either as well. While they were very effective against the BT series and T-26, these tanks were almost 10 years old at the outset of Barbarossa so it is expected. They did still form a large portion of Russia's armor forces.

However, Germany's large success during this part of the war and the massive 20:1 kill ratios claimed are almost entirely a result combined arms tactics, as the common radio in all tanks allowed for more complex maneuvers on the battlefield, as well as allowing artillery and flak units (every division had 2 88's and 1 105mm flak gun) to set up and bear their guns on target. Combined with the domination of the airspace via the Luftwaffe, it allowed the Germans to dominate a technically superior enemy.

On top of this, Russia was suffering in the armor division as a result of Stalin's most recent purges. His fear of the armor core becoming a state within a state meant that many of the leading commanders and engineerings working on the armor development were executed or imprisoned. Furthermore supply issues from unprepared supply lines exasperated the less-than-average supply conditions of many armor divisions at the outset of the war. In many instances, the poor crew training of many Soviet tankers resulted in uncoordinated and frantic firing. In many cases it is reported that T-34's and KV's exhausted their combat load of around 70 shells in under a day of fighting. On top of this supply line stress, many crews had little to no maintenance experience and many tanks were abandoned over perfectly solvable solutions such as a broken drivewheel or a clogged filter.

Tactical application of the T-34's and KV's were also hampered by different ideas of their role. Many commanders felt that tanks should be sporadically given out to infantry as support for anti-tank and armor support. However this proved flawed as it allowed quick target acquisition an frequently resulted in a rifle battalions armor being knocked out in opening stages of a battle. This is a stark contrast to German and Western practices which frequently dedicated an entire division of tanks supporting 1-3 infantry divisions.

However Russian tanks were still formidable, in the proper hands with proper maintenance, preparation, and leadership, they could inflict massive casualties, such as one case where a platoon of 6 KV's ambushed an entire German armor division around 300 miles west of Moscow (I forget the town name) and claimed 32 kills in less than 4 minutes of fighting before the Germans fell backs.

There is even a starker contrast where in the south around the Caucasus, several Austrian/Hungarian divisions were near entirely wiped out by Russian tankers as they lacked the support from the Luftwaffe as well as lacked any heavy flak guns.

It was frequent among German infantry in 41-42 to suffer "tank shock" where simply the sight of advancing Russian tanks could obliterate morale as well as forcing a retreat before any serious resistance could be mounted. It was not uncommon for many untrained crews to crush German anti-tank and machine gun positions with their track to conserve ammo.

I'm going to reply to my own comment now because I'm sure I'm hitting the edge of the Reddit character cap