How does physical resistance work?

What does it resist?
And does it have an 80% cap like other resistances?

It reduces all physical damage, cap is prolly the same but I’m not sure you’ll get close enough…

It resists Physical Damage and Internal Trauma Damage, and is capped at 80%. It is not reduced in higher difficulties.

Is physical resistance any good against getting one-shotted if you don’t want to stack DA (provided the damage is physical)?