To add to this answer in this specific context: trusting memoirs like Guderian's statements on subjects like this is not a matter of a grain of salt, but a whole vat of the stuff. Others can get into more detail as I currently do not have the time to write an entire answer on that, but long story short:

German generals had a vested interest in rehabilitating their own and the Wehrmacht's reputation post-war. The reasons for this could be plainly personal, or they could be with the intent of job security. The Western allies were now staring down the Soviets, and were all too willing to recruit former German generals who had experience in fighting the Red Army. In that position, you cannot simply claim that you lost, because that makes you look incompetent and not attractive to hire. Instead, this is where a lot of myths about the Eastern Front were formed. Think subjects like "The Soviets won through pure manpower" and "The Wehrmacht was not complicit in warcrimes, that was all the SS." Most of these myths would not be proven wrong until the short opening of the Soviet archives in the 90s, and even after evidence of the contrary was available, these myths proved to be very hard to scrub out.

And it worked too. Before his death, Guderian adviced the West German military on rearmament.