3e introduced "Players roll all dice" so instead of an attack roll coming at you, you'd roll with your armor bonus to beat their Attack DC.
I think that's mostly good enough to make it work? Maybe have different "Ways" to defend yourself. Whether it's big heavy armor + Con bonus to be durable, Light armor + Dex + Weapon Mod for parry, or Intelligence+Proficiency to use a mystical barrier.
The dream 6E system I was tinkering with started with the 4e-style "everything is an attack roll against a static defense" (instead of the mix of attacks and saves), but then gave PCs (and important enemies) a limited number of 'saves' per encounter, which work sort of like how Legendary Resistances work for monsters in 5e.
The idea is that each 'save' would make an attack miss you
and would give you some brief benefit. Like the 'Basic Combat' save would let you make an attack miss you, and then you could also do a combat maneuver against the attacker, like to shove or trip or grab them.
The 'Basic Will' save would let you make an attack against your will defense miss, and perhaps give you immunity to emotion and compulsion effects for a round as you get a moment of lucidity.
And then advanced stuff like 'Enraged Defiance' might be a mid-level berserker save that lets you stop an attack and then give you a bonus to damage and let you shove people really well for a round or something.
So because it combines a defensive shield and an offensive boost, you usually want to wait for an opportune moment to use it, not simply spam saves against the first attack.
In this way, HP would be like a passive defense -- your character is just naturally ducking and weaving to make sure that attacks that hit are only grazes, rather than serious wounds, and when you run out of HP, you take a solid hit that drops you.
And saves would be your active parries -- your limited-use ability to avert disaster and possibly turn the tide in your side's favor.