Do you think it makes sense for Niko to kill Dimitri but spare Darko

This is always the choice I make but if you really think about it it doesnt make sense. Niko spares Darko because everyone tells him to forget the past, but then kills Dimitri for betraying him in the past. In hindsight it makes more sense to do the deal ending even though its the worst ending. However I have a few theories on the ending I choose. Killing Darko wouldnt give Niko closure. As he said at the beginning he doesn't know if he wants to kill Darko he just wanted to know why he did it. He gets his answer and realizes it would be worse for Darko to keep living and wouldn't solve anything to kill him. However with Dimitri, Dimitri is always going to be a snake. Niko probably realizes that it's better off for him to be dead than to make a deal with him and get backstabbed again then be a bigger problem down the line. I don't think Niko ever saw Pegorino coming after him as a problem because he just like the five families thought Pegorino was a joke. Let me know what you think of my theory though and why I believe this is the canon ending