Looks like a new contender for MacOS compatibility in this project, https://airyx.org/
It's early days still, but they are making progress at running the full stack of MacOS apps on their BSD base.
Cocoa and Objective-C code compiles and runs, with swift on the way.
Darwin and MacOS binary incompatible at the moment, but on the roadmap.
This is a early dev release.
Windows has React (https://reactos.org/), and now OSX will have airyx.
Also, HaikuOS released beta3 recently, more on that here : https://www.haiku-os.org/news/2021-07-26_media_release_the_haiku_project_celebrates_the_release_of_beta_3/