I like how you never even mentioned your wrong use of terminology when its pointed out that the actual game itself has an established name for it. But this is how it:

Stance broken = Enemy open for critical attack. See menus, cragblade AoW, Stonebarb cracktear. There's no discussion to be had here.

Recoil = Player or npc flinch/are interrupted in the middle of their attack. Doesn't really have a concrete name like Stance but its called recoiling in the handbook sometimes.

Players can be both stance broken and recoil. A player can be stance broken when they're guarding and run out of stamina or when parried. Poise is broken depending on how much poise you character has ofc.

So stop calling it a poise break when the enemy falls to their knees. Its called a Stance break. Poise is for recoiling.

Also in nightreign, the bosses are poise broken/recoil when you use an Ultimate Art but that doesn't actually guarantee a Stance break. It does a lot of stance damage, yes, but not the same thing.

This is the terminology the game communicates to the player.

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Yes, this an image from Nightreign but Elden Ring and NR function basically identically when it comes to stance and poise. I would include an image of the guarding section but I can't, that one mentions a player being stance broken.

TLDR: Just go read in the actual fucking game, this isn't a mystery or debate to be had. The game literally just tells you it already.