During “The First Crown” in Chapter 7, make sure not to free the ghost and hand the crown to Shyka the Many. Keep going with the questline until the end of the House at the End of Time, fight against Nyrissa and, once the fight is over, pick “[Let Nyrissa go] Promise to never invade my lands again - and I'll let you go. One way or another, the thousand grains of dust have been collected. You can take the cup and gain your forgiveness from the Eldest.”, enjoy! You will skip Chapter 8 and go straight to the epilogue. This will preclude the Flaming Crown achievement but, unless you want to replay the game for it, you can keep a save before the fight against Nyrissa and strike a deal with her to proceed to the next Chapter and ending/achievement.
Credit to Starsong for their
guide.