[2020] 100 ergo, 2.6kg, nothing else equipped and my super trained PMC cant hold his rifle for a single minute?

ADS stamina drain is just insane. I build a super small m4 with 100 ergo 2.641kg (loaded), have no gear whatsoever equipped (total weight 2.6kg/70kg) and my highly trained PMC still cant hold his rifle for at least a minute? Even unloaded (2.1kg) I cant hold it any longer, how are you supposed to fight if your dude is too week to hold a gun that is half the weight of the USMCs standard infantry rifle?

https://preview.redd.it/lowi9aur6mm41.jpg?width=1742&format=pjpg&auto=webp&s=dbfcd490e8fe02ea4289bdea6539869bf98eb702