For max inventory space unlock carry that weight in the survival tree after 6 upgrades, doubles your crafting materials traps and throwables capacity. Up the ante skill in ranged tree increases ammo capacity which is crucial for longer missions. Something interesting about scrap, you can hold 20 max with upgrades so always prioritize it for bike repairs and weapon crafting

Making space is all about smart usage, craft those bandages and explosives whenever materials are getting full rather than holding onto everything. Good idea to check inventory before missions, keep health items and scrap as your priority since common materials show up everywhere. Remember to burn through basic supplies first, keeping rare items for tough encounters or emergencies

Those materials aren't doing any good just sitting there so craft regularly especially before heading into nero checkpoints or clearing ambush camps