I say this as someone who loved Elain in the original trilogy, but I absolutely hate her in ACOFAS and ACOSF. Her and Nesta's fight scene is truly baffling and reveals a lot about Elain's character. Elain was the instigator of that fight and said incredibly cruel and hurtful things, yet she pulled her fake tears and cried to Rhysand about Nesta? I'm not denying that Nesta said some cruel and hurtful things, too, but so did Elain. Where was the accountability for Elain? Elain has a habit of making Nesta's trauma all about her, which is exactly what she condemns Nesta for supposedly doing. Elain's such a hypocrite. This whole fight scene just really proved that Nesta is never exclusively the one in the wrong - she's just the only one ever held accountable by the narrative.
There's even scenes where Nesta's not in the wrong at all, yet she's condemned by the narrative. Case in point: the Nessian interaction in ACOFAS. Nesta said nothing cruel or hurtful - Cassian did - yet Cassian threw a pity party for himself in front of the IC, so they all thought Nesta was in the wrong when, really, it was Cassian in the wrong.
Another example is the "Everybody hates you!" scene. Once again, Nesta said nothing cruel or hurtful - Cassian did - yet Cassian and Feyre threw a pity party for themselves, so the narrative paints Nesta as being in the wrong when, really, it was Cassian in the wrong.
No character is perfect, but it's the way every other character says cruel and hurtful words to Nesta while simultaneously crying about her hurting their feelings and that's just a turn-off for me on so many characters.