[adwn]

> [The soviets] lost the most soldiers [...]

To be fair, the major reasons for this were that the Russian military leadership was utterly incompetent during the earlier stages of the war [1], and that they suffered from a serious lack of equipment and material. "Number of casualties" and "years spent fighting" aren't good indicators of military effectiveness.

[1] That's what happens when you liquidate your military elite or put them into gulags because they are on the wrong side of your class war.