The abominations part was mostly a direct consequence of failing the Witness, not a part of her agreed freedom. Eramis was let out of stasis to gather the Relics of Nezarec so that he might be revived, likely so that the Witness might learn of the Veil’s location. Her House becoming Wrathborn or Scorn was a direct punishment for her failure in this task, with the Witness even ensuring she was forced to watch the latter as her old comrades were raised from the grave. She wasn’t given a choice in the matter, once she agreed to serve she lost all agency until Defiance where they randomly decided to revert from the character arc in Seraph where Eramis’s pain won out over her desire for her people’s future. Eramis made her decision in that turning of the key and then in one cutscene and a lore tab Bungie writers decided to undo all of that.