If you'd been playing right since Early Access, chances are your Hades II ending involved Zagreus and some shenanigans that seemed to take away much of Melinoe's agency in how to deal with Chronos. That ending was changed rather quickly, with new dialogue, changed scenes, and more. However, this wasn't part of Supergiant's original plan for the ending.
"Our post-launch patch was created in response to player feedback," Supergiant's creative director Greg Kasavin told GamesRadar+. "Hades 2, like its predecessor, was designed for Early Access development from the ground up, meaning we conceived of it as a game where listening to and responding to player feedback would be core to the development process."
"Hades 2 is also a game that explores the effects of time," Kasavin continued. "Ideas around different outcomes and possibilities that might have occurred, and having to move forward past setbacks...We were thoughtful about such themes when enhancing details of the story in response to player feedback."
So, if you got the first ending and don't mind it, it doesn't seem like it has been fully wiped from the canon. However, if you want the second ending to feel wholly yours, then it can be. Hades II's ending had quite the monumental task to accomplish, and while the first draft might have fallen short to some fans, Supergiant showed it's always willing to listen by making some changes.