It seem that developers do consider the use of an infatry and support weapon as "combined arms".
I'm well aware. Which is why I mentioned it.
Ive never had problem with the maxim being able to supress, the only time i find the maxim to be trash is in the late game when there is yellow cover everywhere and squads can literally walk up to you without getting supressed.
Oh maxim suppresses alright, it just doesn't pin within the amount of time that it needs to to keep itself alive. All there needs to be are two panzergrens (or any unit with a deadly grenade), a bit of space between them, and enough munitions to throw one. No matter how you micro the maxim, without Suppressive fire, you're not going to be able to pin both of them before they can get close enough to throw the bundle grenade.
It gets worse the more deadly the opponent is, which is why I said that you need time to ready and pop suppressive fire. Because of the deathloop, if you don't suppress long range blobs quick enough, your MG is dead as soon as the first model drops. This wouldn't be an issue if you could at least retreat it, but unlike the MG42 the gun does not teleport to the next retreating model and instead the surviving members have to run back and pick it back up (this should really either be a feature of all MGs or NO MGs, because as far as I know, teleportation technology hadn't been perfected in the 40's yet. Or in the 2020's, for that matter).