I hope she is doing all this as a way to kill The Jailor/The maw, but not because she is good and she is thinking in other people.
She is saying a lot that Life is Pain, i dont think that means that Azeroth is bad and Shadowlands is good, i believe she is saying that existence is painful, and she dont want that anymore.
She jumped from Icecrown Citadel, died and ended in The Maw. When she jumped she wasn’t expecting for heaven, she was expecting nothing, she was expecting to become nothing.
I Believe she is doing all this to find a way to be erased of the creation. The Jailor and The Maw should be the place where bad souls like Sylvana go in the afterlife. I Believe she is hoping that once the Maw and The Jailor are destroyed the arbiter wont have anywhere to send her and will have no option but destroy her soul. So she will finaly have her rest.