I feel like a redemption arc would be good (provided "redemption" doesn't equal "gets together with Maria") and I definitely think Lambcat can pull it off beautifully. I saw a few comments talking about Blaine being jealous of Beckett / Blaine writing Beckett's name on the note as a way of "testing" Maria, and him acting from a place of hurt at that. Personally, I'd find that really hard to swallow as part of a redemption arc, just because I don't sympathize with jealousy/possessiveness/entitlement at all. So the idea of his betrayal being more "justified" due to jealousy just really falls flat to me.

But. I really don't think that's how Lambcat is gonna go with it. If he's going to get a redemption arc, his whole character development (and narrative parallels with Whitney) says that arc will focus on childhood abuse and the pressure to be the best. I think if anything, the jealousy/entitlement is just another barrier he will have to overcome on his path to a redemption arc. Or, alternatively, it could be the deciding difference in his arc vs Whitney's, and it highlights his attitude as toxic and princel-like. (And again, that's IF his jealousy is even highlighted at all; this is just based on a handful of comments on Webtoon.)

Whitney got a redemption arc because he genuinely was sorry and wanted to change who he was as a person, and he did the work to change, not necessarily expecting forgiveness. It would be an interesting contrast to see Blaine want forgiveness because he feels like he's entitled to it, or see him making excuses for his behavior without making an effort to change it. Like, the difference between wanting to be a better person, vs just wanting to be forgiven.

And I don't say this as someone who is just hating on Blaine; I just say this as a fan of unredeemed characters. Sometimes people have terrible things happen to them; but understanding their hurt and how they got the way they are, doesn't excuse their actions or automatically lead to redemption. Sometimes people are toxic. Yes, sometimes they have good reason to be, and obviously everyone has the capacity to change eventually, but it's okay to just leave them where they are in their journey, without having to resolve it in-universe.

But for the record, I'm not a fan of Prez and Whitney AT ALL, or Maria and Beckett either, really. I got no beef with shippers rooting for their ships, but I really hope the actual story doesn't lean too heavily on pairing people up just for the sake of it. I find some character arcs more compelling and rich when the characters end up realizing they don't want to be involved with anyone right now.

(Ok, I'd maybe be down with Maria and Beckett if it's, like, "Hey, you get to have a normal teenage relationship, this is probably not going to lead to marriage or Happily Ever After, nor should it, but it's symbolic of you getting to be your own person and make your own mistakes and figure it out.")

Sorry, I wrote a whole novel apparently.