I wasn’t commenting on that part of your assertion. This verse does not say that the many are working iniquity.
You said this:
Therefore, these "many" are saints who, through the practice of iniquity, kill their agape cold and dead, fail to endure to the end, and are not saved in the end.
Matthew 24:12 doesn’t say that. let’s look at verses 8-12.
“All these are the beginning of sorrows. Then shall they deliver you up to be afflicted, and shall kill you: and ye shall be hated of all nations for my name's sake. And then shall many be offended, and shall betray one another, and shall hate one another. And many false prophets shall rise, and shall deceive many. And because iniquity shall abound, the love of many shall wax cold.”
Matthew 24:8-12 KJV
https://www.bible.com/1/mat.24.8-12.kjv
Those working iniquity are they who deliver you up in verse 9, those who betray and hate from verse 10, and the false prophets from verse 11. I think you understand this because you reworded your last response to remove “ through the practice of iniquity”. If Saints aren’t working iniquity, then you can’t say that people who were once Saints have fallen away to be condemned. That means the point you wanted to make falls apart.