Here to confirm the words of Anon from 10 October 2022. You actually can save both the Queen and get the Glass key without it being broken, even if you *did not* give the first part of the Lexicon to the Queen before being sent to the Abyss. You have to go to the Temple first, avoid going into the room in the West, and instead go straight into the room to the East with the closed door. There you only need to notice the hidden door and lockpick the chest where the Glass Key is kept in, loot it and then head out of the Temple altogether to save Queen Galfrey. After which, you can simply head back to the Temple, kill the enemies there and take the "Key Crystal in the room in the West of the map. This way, you have both the Glass Key and the "Key" Crystal safe and sound, and neither Irabeth or Queen Galfrey have to die, even if you didn't momentarily give up the Lexicon to the Queen.

"If Irabeth is not in Iz with Galfrey and you do not go to Galfrey first, Galfrey will die. [Unclear what sequence of choices leads to Irabeth not being present - please add context if this happened to you. Possibly related to the crusade project in Act 3 to help Irabeth?]"

- Irabeth is in Drezen, if you can persuade the queen not to revoke the commander rank at the end of act 3 (before Alushinyrra) - only happens as an angel or aeon (high Diplomacy check)