(Spoilers obviously) Described here, the truth of the Age of Stars ending is not that the Lands Between would be plunged into a thousand years of darkness and cold, but that Ranni (and likely the Tarnished PC) would embark on a thousand years journey with the Golden Order they've obtained, taking it far away, so that the people of the Lands would no longer interact with it directly; something she believes would be an improvement over the current situation.
(Spoilers obviously) Described here, the truth of the Age of Stars ending is not that the Lands Between would be plunged into a thousand years of darkness and cold, but that Ranni (and likely the Tarnished PC) would embark on a thousand years journey with the Golden Order they've obtained, taking it far away, so that the people of the Lands would no longer interact with it directly; something she believes would be an improvement over the current situation.
(Spoilers obviously) Described here, the truth of the Age of Stars ending is not that the Lands Between would be plunged into a thousand years of darkness and cold, but that Ranni (and likely the Tarnished PC) would embark on a thousand years journey with the Golden Order they've obtained, taking it far away, so that the people of the Lands would no longer interact with it directly; something she believes would be an improvement over the current situation.
I haven't played the game (or previous related titles for that matter) and have a tentative grasp of the lore, but per the impression gained from the themes;
Rather than darkness and oblivion, Ranni wishes to bring rest and respite by removing that which everyone has been fighting over. Ranni ending is literally "good night".
(Spoilers obviously) Described here, the truth of the Age of Stars ending is not that the Lands Between would be plunged into a thousand years of darkness and cold, but that Ranni (and likely the Tarnished PC) would embark on a thousand years journey with the Golden Order they've obtained, taking it far away, so that the people of the Lands would no longer interact with it directly; something she believes would be an improvement over the current situation.
I feel like this wouldn’t help the Lands Between nearly as much as she thinks it would. Imagine coming back a thousand years later and it’s all OOPS SCARLET ROT EVERYWHERE.