C) Yes Maxims deal more damage then mg42. But mg42 pinns better and has more "side-range" from left to right.
IIRC MG42s suffer much more from supression and pinning than the Maxim DPS wise.
Also I watched the replay, you do know that grenades do less damage when a squad is in open cover, right? If you know that why are you wasting muni, when you can just walk closer with falls and deathloop the maxim?
Also being afk for the first minute doesnt help either.