One thing about me is that I typically find characters who are genuinely bad people and who chose to be better much more interesting than misunderstood antiheros. Allow characters to actually make real impactful mistakes and bad choices. Allow them to be unlikable. Allow the discomfort of reckoning horrific past choices with better future ones.
I find that someone who was god awful and chose for whatever reason to be better, to try and help fix the harm they caused and reduce similar harm going forward, who struggle and struggle as guilt and frustration eat at them, and yet don't forsake growth for the sake of the safety of stagnation, is much more interesting and complex than someone who killed people but it's okay because the people they killed all deserved it so they're fine the way they are.
If your character makes one shallow oopsie and grows from it that's not redemption that's an after school detention. Redemption should be messy and difficult but ultimately worth it. You will only be able to pull off such an effective redemption if you aren't afraid of your audience having mixed feelings on the character in question.
