I dunno if it'd be overkill but i think Edge could perhaps work like Death Strike from WoW's DKs, which heals you for a small amount baseline but scales up with the damage you took in the last 5 seconds.
I don't know if it's gonna fit with the current game content, but that's a reaction based lifesteal playstyle that i very much enjoyed.
As a matter of fact, didn't they say that they wanted to introduce ''parries'' to tank defensives before endwalker?
