Yeah - when I was still uncertain about a Cozy redemption, one thing I was sure about is that I didn't want it backstory-based like Starlight's.
As for Sombra... as much as I disliked how shallow he was in his first appearance originally, I did eventually come to appreciate him being kept at a distance and depersonalised - it and various implications likely formed from plot holes let me imagine that he was worse than the show's rating could directly support, a true Pony Hitler.
The comics went a different route, and I guess that worked for them. Season 9?...well, at least he was shown as highly powerful and competent. ~~And I treat that episode as in-universe fiction anyway.~~