With the stamina system in-place, this should be the overarching restriction on what players can carry.

The current 1x ranged weapon, 1x melee item is terribly immersion breaking. Also the ability to magically have an axe or rifle stuck to your shoulder should be removed.

Recommendations:

• Make each shoulder a full-featured slot with no restriction on item type (let players be a 1x shovel/1x axe base building guy, or that military guy running 2x weapons over shoulders to allies)
• Make each item going on shoulder require a strap of some sort. This can be rope, improvised rope, weapon strap etc

With these game designs in-place the game will be much more realistic and put more character self-balancing due to the stamina system.