I know that Carrie said some really hurtful things to Julie, and there is no excuse for that.
However, I will die on my Carrie Wilson Redemption hill.
She lost the mother figure in her life, and subsequently her best friend (Julie) as she withdrew into her own grief. Carrie’s father experienced unimaginable trauma at a young age and is still dealing with that; Carrie has no idea how to process her grief. So it gets channeled into this antagonism and cattiness, particularly toward Julie. (Again, not an excuse, but it’s a source.)
Carrie knows how talented Julie is. She knows the kind of person Julie is. In ep. 3 when she says to Nick, “Julie’s no friend,” she’s clearly hurt(ing). Honestly at this moment I kind of theorize that at times during Julie’s year of silence, Carrie was thinking of her and wondering how she was coping, though she maybe felt like that wasn’t her place to inquire anymore, that she and Julie were to estranged anymore.
Then we have her ovation at the Orpheum. The soft, proud smile and gentle applause. She’s clearly happy to see her once friend achieve such a feat and with a song started by her (their) mom. To see her rise from her grief and do something phenomenal. I think in that moment Carrie isn’t resenting Julie anymore but admiring her; surely Carrie wants to reach such a point. She must be tired of being mean and nasty. Maybe it’ll still take a while, but I have high hope for her.