"Oathbreakers" are evil, by definition, "oathbreakers" are not.
A oath of conquest paladin that broke their oath for good reasons, would be more suited for a oath of redemption.
All serious tho, one of ideas I know I will never be able to do is to play the same Paladin in 3 succesful campaigns in one setting, first as Oath of Conquest, then Oathbreaker, then Oath of Redemption. I first it's a better growth if there is a transition phase before adopting the Redeption.
The problem with Redemption is that it's an externally-focused oath, trying to redeem others. A conquest paladin having an "am I the baddy" moment and turning into a redemption paladin is like a douchy bully who suddenly finds Jesus then tries to convert people without apologizing for the years of bullying.
D&D needs an Oath of Atonement which would be specifically focused on making up for the shit you did as a previous less-than-moral paladin subclass (mostly conquest, sometimes revenge, occasionally crown or devotion).
How often are we gonna have this conversation? Becoming an Oathbreaker is not the same as breaking your oath. If you actually read up on how you become an oathbreaker, you might understand why it's an evil only subclass.