I feel Cazador-dead Spawn-Astarion has a pretty good resolution to his story. Sure, he would like to walk into the sun again one day, but it does not seem to be his top priority as he has reclaimed the night for himself. If as the God of Ambition, you suggest him to pray to you, he declines because he has learned that too much ambition is harmful. - The same lesson Adventurer/Professor Gale has learned. Also I can't agree that Gale gets out free. He gives up on his dream of understanding everything the Weave has to offer that is kind of a hard thing to do if you have an overachiever disposition.
I don't know astarion enough to say one way or the other. But gale made intentional choices that led to his punishment it wasn't some random act of chance like karlach. She wanted a job and it happened to be with gortash who sold her as a slave to zariel who then experimented on her to create a demon hunter soldier with an infernal engine for a heart. Nothing about her story was jn her control where as gales lust for power led to his current issues. Wyl is similar but his was a lose lose situation. My point being if gales ending is he can't chase after magic that's a proper ending where he can move on and find other ways to live. Karlach literally can't and her only mistake was she happened to end up working for gortash and she was way too trusting.
