If you want turn based, I'd look out a copy of the old V4V games (Utah Beach/Gold Juno Sword/Market Garden/Velikiye Luki) and run them in dosbox. Easy to play, but due to a we-go turn sequence much less hampered by turn-based compromises than normal... (simultaneous move/phased combat within the turn, long moves spanning multiple turns are possible).
If you are prepared to consider non-turn-based then I'd suggest BfTB - at least download and try the demo... the basic game play is straightforward and therefore suited to new players, but a deeper understanding of the fundamental principles of command & logistics allows increasingly nuanced plans. Although the demo only has a single operation, it is playable from both sides, and the entry of reinforcements and availability of supply can be tuned to make the attacker's job easier or harder.
Although the unit scale is essentially company sized units, handling a Corps sized action is relatively simple, as units act on existing orders till complete/abandoned/cancelled, and the AI will handle orders for the subordinates of the unit given orders by the player (in accordance with player specified instructions).
Other games are also good, but I find pure turn-based offputting and frequently rather tedious, particularly in monster-game format...
Ultimately Id suggest you try as many demo versions of stuff as you can, then re-ask for advice with indications of which play styles you liked best.