I see shows about military training and the soliders are loaded like pack mules. I always wondered why they carry so much stuff.
In combat, lighter is better. German troops in WW2 carried very little. Also US troops in the same war carried the bare minium.
Dry socks, rations, grenades, watter and ammo.Ponchos for shelters and there you go.
Nowadays, as in medieval times, modern armies have to contend with primitive infrastructure since they aren't fighting in Western Europe, usually.