Does your in game character know that my fighter used a Battlemaster feature, a feat or some other thing to deal the completely opaque amount of damage that your character cannot possibly quantify?
Again, unless characters in the game world have glowing numbers popping out of their heads Final Fantasy style during combat, NOTHING you narrate is EVER tied to mechanics. It absolutely cannot be. Combat is far, far too abstract.
See, because, no, the weapon damage is NEVER consistent. I stab one human with a sword and kill him instantly. I stab another human with a sword and barely scratch him. In both instances, my character did IDENTICAL actions, same die rolls, same damage rolls, everything is 100% the same from my character's point of view. But, because of completely invisible (from the POV of the character) forces that cannot be quantified or measured in any way (again from the character's POV), these two naked humans who look identical in every way, will respond completely differently to my attack. One dies instantly with a sword to the chest, the other is barely scratched.
Now, how do you explain that?