I'm going to state the obvious and ask and have you bothered to look at any of the kajillion books about world war 2, the few dozen WWII magazines or Army Historical Society or national archives?

pretty much standard resources if you're going to get into historical based games

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https://inflab.medium.com/eastern-front-maps-of-world-war-ii-17f4a26545e9

https://www.nationalarchives.gov.uk/help-with-your-research/research-guides/military-maps-second-world-war/

https://guides.lib.berkeley.edu/germancapturedmaps

http://shop.strategyandtacticspress.com/

https://www.onwar.com/wwii/maps/efront.html

https://www.amazon.com/Atlas-Eastern-Front-1941-45-Military/dp/147280774X

time Life series were great, covered the whole war and major campaigns

https://www.amazon.com/Third-Reich-21-Volumes/dp/B000WOZZQ8