So...two things.
Your question seems to assume that all German soldiers were die-hard committed Nazis. This was almost certainly not the case.
I'm pretty sure this question doesn't have an answer that can be applied to "Soviet Soldiers." How ideologically committed somebody is to the Soviet Union probably depended on a lot of factors, like age, class origin, nationality, upbringing, personal beliefs, and the proximity of an NKVD commissar.
Whether they were motivated or not, keep in mind that the enemy perceived them as sub-humans deemed for extermination: that might give you some motivation to fight.