Yes they do. At least the maintainer for the S8 releases them regularily.
That's not something i would worry about. When the unofficials get a stable state they're fine and only get the latest patches from LOS. I'm running customs since 8 years and i never had problems.
I'm running the unoffical one on my Samsung S8 without issues since it's been released. Unofficial only means it's not supported and compiled from the LOS developers. They're safe and stable
I'm not sure how stable it would be but some people managed to get version 3 to run the SteamDeck. Which is impressive IMHO