What's the point with that quite lackluster story in Endwalker?

[Lurina]

If there is no excessive and unnecessary force, then there is no need to argue about collateral damage. Venat did what she thought she had to do to stop the others from making that final sacrifice.

Collateral damage makes an action morally complicated, regardless of the intent and presumed necessity of the action. Someone who is willing to shoot into that crowd to stop a worse tragedy is not a hero, even if they believe their intent to be heroic, because they have still brought pain and death to the innocent themselves. Whether or not it's even permissible is the controversy inherent to the trolley problem, which you're almost certainly familiar with if you've spent any time online.

We've circled in such a manner that the only way I can think to respond is my looping back my original opinion.

Personally, I will find a "necessary evil" on that kind of scale being framed as heroic in the way it was kinda creepy and offputting no matter what. Doing a bad thing to prevent a worse thing don't make you a morally better person, just a more pragmatic one.