The last hit takes you down after no appreciable loss of ability before that call it what you want.
The last hit is both a crit discovered with a heros skills and was preceded by many many many attempts all bouncing off armor.. D&D ablates hit points as luck runs out (and now has relatively minor crits)
And for you every every every every single attack is a wound.. AND every every every every hero is a tough guy hero.... zzzzzzzzzzzzzzzzzzzzzzzzzzzzzzzzzzzzzzzzz how fun you get to decide for your game play and not for everyone else.
My characters I will continue picture turning accurate attacks into some sort of miss causing fatigue/luck loss and sometimes minor wounds. OR even if I have a regenerative hero
like a long tooth shifter not so minor wounds.
I guess my problem with a "lucky" character is that it kind of ignores the luck of the attack roll. For me the luck is the monster rolling a 1 and missing or my character rolling a save and succeeding. That was lucky.
If you describe your character as luckily dodging out of the way of a successful hit then it just seems...kind of fake to me. Its like the Black Knight getting bits chopped off while still refusing to acknowledge that anything bad was happening to him, although probably not because even he admits to a flesh wound.
It also clashes with any luck mechanics in the game. A lucky 5e Halfling can reroll an attack but your lucky character cant. A Luck Blade gives you a bonus to your saves and Wishes!
But the good news is that at least a Cure Light wounds can still heal luck damage, so thats lucky!