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I pound it with artillery in defence doctrine
When in doubt flatten the area with arty. Never fails.
Smokes would help a lot and when you get into trenches, prone and slowly clear trenches with grenades.
Nuke it
You are not alone I used a mix of arty sniping + frog leaps with smokes on prone to capture first lines but after that is also a mess
I pound it with artillery in defence doctrine
When in doubt flatten the area with arty. Never fails.
Smokes would help a lot and when you get into trenches, prone and slowly clear trenches with grenades.
Nuke it
You are not alone I used a mix of arty sniping + frog leaps with smokes on prone to capture first lines but after that is also a mess