Yeah, nothing about Karlach seems to suggest she has a happy ending sitting there but unimplemented. I've mentioned before that Karlach's ending is tragic but fits much better with the themes of BG3 back in EA than it does in release -- what is the worth of surviving if you sell your soul to do it? Karlach is the one character who would choose not to compromise her morality and ethics just to live longer, and, so, gets to die surrounded by her friends after having saved the day. This is really powerful! Her ending is tragic and memorable, the one bit of my BG3 ending that I can recall vividly. If anything, the issue is not that Karlach has a sad ending but that she's the only character to be forced into a sad ending.