It wasn’t a global flood. It was hyperbole. 2 Peter 2:5 says it just covered the world of the ungodly. “World” is generally used locally in the Bible as well as “the earth” meaning a large area of visible land.
We can see that in Genesis 8:9
“But the dove found no place to set her foot, and she returned to him to the ark, for the waters were still on the face of the whole earth. So he put out his hand and took her and brought her into the ark with him.”
When verse 5 said:
"And the waters continued to abate until the tenth month; in the tenth month, on the first day of the month, the tops of the mountains were seen."
I do not care how local you think the myth of Noah’s Flood was supposed to be, as that fact is immaterial to the point you continue to miss. That flood still would have killed innocent people, and the story frames this as a morally just action. No amount of quibbling over linguistics will change that.
The amount of excuses needed to ignore the plain implications of a passage is really telling. One could take the Old Testament as it appears: a series of books written and edited (and redacted, and co-opted, and edited again) as the religious and cultural canon in the Iron Age for an otherwise obscure Levantine tribe, with morals from a different time and place unsuited to our modern sensibilities. There are many such books and traditions from all over the world that contain tales just as horrifying as any in the Old Testament, so it would not be without company.
But the apologist wants us to believe that their ancient stories are actually true, and so they have to invent all these insane reasons why clearly immoral actions by their book’s main character are totally justified. This is the sort of position that can only come about when someone decides what they believe first and then looks for rationale afterwards.