ML is....

Reading the spoilers, it's Dante who's the ML. Why? Well in short, OG FL is totally evil and wanted to return to her world where her brother is the Crown Prince and full of magic so she literally brainwashed all three MLs to kill FL in each timeline before turning back time over and over again. Dante was the first one who was able to snap out of the brainwashing first after each of FL's death and filled with so much anguish and regret of the amount of murders done to FL. Dante was also the one who tried to remove the brainwashing onto Benedict and Lucian but those two were in so deep of not being chosen by the FL that it made it even harder to snap them out of it until Dante was able to get to Benedict. Benedict then devised a plan to place something in this magic circle that reverses time where it snaps Lucian out of the brainwashing too by giving him his past regressions of FL being killed by the three of them multiple times. FL actually got some magic in her after being regressed for the nth time so once she stepped into the magic circle, it gave a backlash towards the OG FL that killed her instantly. I think Dante is the one out of the three who deeply regrets and seek atonement for FL so he thought killing himself to stop the magic circle will make up for it but since FL stopped it, she chose Dante to have him by her side to atone. Lucian is basically kind of an Eckles and Penelope situation.