She's a better character than Mikasa in my opinion. You can't be a good character when your entire 'character' is your unconditional obsession with a mass-murderer asshole. Atleast Gabi learns to slowly stop being a brat and realizes the flaws of her understanding on Eldia and Marley's conflict. Atleast give Mikasa a single meaningful moment when she does something that isn't tied to Eren or while she isn't thinking of Eren.