No, none at all, I'm afraid. That would need a really dedicated person interested in working on both Qt and Krita. We did have a summer of code project where a

No, none at all, I'm afraid. That would need a really dedicated person interested in working on both Qt and Krita. We did have a summer of code project where a student updated Qt's painting code to work with Apple's openGL implementation, though. And Krita shouldn't be more unstable on macOS than on Windows or Linux, but it doesn't get tested as well, and there are so few macOS developers who want to take a hand. Personally, I develop on Linux but use Krita on Windows, when I find time to work on my own comic. The macbook pro only gets opened to make builds or fix the occasional macOS-specific bug.