Something similar with the companion but for the player and that is armor for the player ideas (Blallistic armor level 1-4, Fire Retardant armor level 1-4, Stealth Armor level 1-4 “where the user will be less seeable and reduses the noise of the user too”, Juggernaut armor " where the user has a 50% resistance of damge but is 15-25% slower for movements, Combat hazmat armor level 1-4.
That goes into the same direction as my idea in another topic:
Btw. I don’t know if you already unlocked everything, but these resistances you mention actually exist by crafting apparel.
But like you said, a system for the character which is similar to the companion where you can equip some upgrades for your character that make use of certain apparel with unique abilities or resistances would be great.
There could be for example helmets in different classes (simple, common, good, excellent to unique) and optics that can be weared over the selected hairs and which give additional values for whatever.
I made some more examples in the linked post above.