Well, lucky for us she can do both. She’s still got ONE 1-up left at her disposal last I checked (assuming her resurrection only takes two of her remaining Val’kyr to pull off, and not all of the remaining 3); so she can both “Die” and still have an opportunity to find her way out of that Chaotic Stupid Villain role (and tbh, if she had no more extra-lives at her disposal any efforts she takes to GO that route would have more meaning; as those efforts come at more risk to her).
For now though, whatever she has planned she’s in it for the Long Haul. Teldrassil was not just her “Fall of Quel’thalas” moment, it was absolutely her “Broken Shore” moment as well. The moment she decided that there was no going back, and ensured that there wasn’t for her with a single monstrous act. We’ll likely have to deal with whatever her “True Objectives” are (and their outcomes) before I can see any story afterwards for her happening (and despite surviving BfA, I doubt she’ll be part of the Horde OR Forsaken after its conclusion … at least for a while).
And to the OPs point, Summermoon or Tyrande would be the best bet to take her extra life. Depending on how the story goes, Saurfang or Blightcaller might be in the running as well. Though … I would laugh if Wix ends up just shooting her in the back when he realizes she’s not profitable anymore.