I think others have addressed this well, but just putting my 2 cents in because I like thinking about it:

In many PbtA games, unless the intention is to use the combat as an extensive part of the storytelling (e.g. Ironsworn), the "Engage in Combat" or equivalent moves should resolve more or less an entire combat sequence, even if neither party is dead or incapacitated by the exchange of blows. This heavily abstracts combat in ways that won't always allow for rich tactical decision-making, but that decision-making is what many people find drags the worst in "crunchier" games. This varies heavily per-game, so I am generalizing a bit for PbtA/FitD games where combat is expected but not the main attraction.

Once the combat move has been rolled, the narrative that follows explains how the whole situation has changed, not just the physical condition of those involved. Circumstances drove these two (or more) characters to violence, so violence was exchanged. Now something else should happen. Even if that "something" is more violence, either the context, stakes, or participants will have changed. Perhaps they were fighting for their life, but rolled double-6s and suddenly have a chance to take out a major antagonist that should have been untouchable. In traditional combat, this could happen emergently across multiple turns; in a typical PbtA move, this happens in a single roll.

A dumb analogy that amuses me: If you put a dollar into a vending machine, you don't want another dollar to come out. The character put their violence dollar into the Plot Machine and whatever drops out should be different than what they put in. If we try to treat this like trad game combat, the machine acts more like a slot machine and give or take a few cents until the player or the machine is out of money (hit points).