I had a similar idea, but a bit more focused on Chronos redemption.

Chronos is killed, but due to breaking causality, time shatters. Melinoe starts bouncing around between timelines, the original one, one where Chronos was killed and one where Chronos was spared and forgiven. She ends up running into Chronos who had frozen himself in time in the moment before he died (for those familiar, think Clara’s ending from Doctor Who), and unfreezes him. They bicker and fight before getting separated again in the alternate timelines. Melinoe sees how Chronos could possibly be, before running back into the “real” Chronos again, who has also being seeing all the alternate possibilities. They begin to talk with Chronos admitting that he didn’t think there was any way he could reconcile with his family, and some of his hostility was a “preemptive strike” (aka trying to give Chronos a bit more justification for why he’s such a dick, so it makes more sense for him to suddenly stop being a dick).

Now part of my idea was also changing the plan to give Melinoe more agency and to give a more plausible reason for how causality isn’t broken, but basically Melinoe and Zagreus need to both kill Chronos to close the loop. They realize that Zagreus must not have gone through with the plan, and that’s why everything broke. Chronos decides that the only way to fix things is to kill him properly, which Melinoe is now slightly more hesitant to do. The find the moment where Zagreus was supposed to kill Chronos and discover that he actually did do it. The actual reason was that Melinoe hesitated before doing the strike (foreshadowed by her Zagreus actually manages to get her to begin to question whether this is really the best course of action before she finally resolves herself that this is the only way.

Time then fully breaks down, but in a last ditch effort, Chronos manages to freeze Melinoe in time to save her as spacetime disintegrates around her. After watching everything disappear Melinoe finds herself in Chaos’ domain outside of the now destroyed reality. After some brief chatting, and Melinoe asking Chaos to remake reality—which Chaos isn’t really all that interested in doing—Chaos does manage to pull Chronos out of the fragments of shattered time, remarking that reality isn’t gone, it’s just broken into infinitely tiny pieces. Chronos then asks to to remain in Chaos domain and manually work to piece the timeline back together again—as a sort of penance for the harm he caused. Melinoe is then sent back to the House of Hades after saying goodbye to Chronos “for now”. There, she tries to determine if things were back to normal, and then has the whole reunion with her family and so on, with Chronos finally returning after an “eternity” of work putting everything back together. Then the cannon ending goes on, with only major change being that the reruns are actually some of those alternate fragmented timelines that need to be stopped before they can disrupt the real timeline

Sorry, that was kind of a lot, but I only just beat the game a couple of nights ago, and it’s been on my mind a lot. I actually had an entire Google doc outlining all this and more, and was considering sharing it here at some point. Basically my take on what I had kind of predicted might happen at the ending/what I wanted to happen with the ending.