It's really strange how a chunk of the fandom has gaslit themselves into believing a redemption is strictly about being forgiven and nothing else. In reality, redemption stories cover a range of subjects that may not even involve forgiveness at all, they're primarily about the struggle to become better.

Hurricane Fluttershy is a redemption story about Fluttershy overcoming her anxieties to make up for her weakness to help make a difference. No one was mad at her or cared about her performance except maybe Dashie, forgiveness was not a factor.

Discord's redemption isn't about forgiveness either, Celestia and the m6 forgave him upfront and released him under conditions because he might be useful. His redemption story was about learning that friendship might actually be valuable to him as a person who has never had any friends, becoming friends with Fluttershy is how he redeems himself.

Likewise Starlight's isn't about forgiveness, not externally anyway, she still harbored massive guilt and had to forgive herself similar to Luna. Her redemption story is about learning all about the magic of friendship she missed out on in her youth and overcoming her crippling insecurities in order to be a more effective leader and friend. Becoming Twilight's student is literally her "training arc" leading to her redemption where she uses everything she learned about friendship and herself to save the world from certain doom.

Then there's Sunset, her redemption is strictly about forgiveness. Her struggle was simply trying to convince others that she changed. This seems to be the gold standard for this chunk of the fandom, but there's a few reasons why it's my least favorite redemption. One, Sunset was a terrible villain which hurt the impact of her redemption. Two, her change was instantaneous, she had no internal struggle where she was forced to reckon with her views, only the external struggle of people being mad at her. Three, the people mad at her were justified in their anger because of her purely malicious actions so I feel zero sympathy for her.

What makes a great redemption is the journey toward that redemption. The growth that the characters must undergo to reach that redemption is what I consider the real meat of a redemption arc. Fluttershy had to stop being a lil bitch, Discord had to open his heart to friendship, and Starlight had to unlearn over a decade of trauma. They were endearing and sympathetic to watch and I was rooting for them every step of the way. Meanwhile Sunset just had to be a better salesman. I would feel for her more if her change wasn't instant, thus unearned which she then turns around to beg forgiveness with, it feels dirty. A better motivation would have helped open a lane for growth, but no, she was a bland power hungry villain. Her redemption essentially has no substance.

Anyway Starlight's redemption is my favorite and I think it's very well written overall.