Just saw a news in the render meeting notes and I think I may mention it here
It seems Cycles X will be merged to master around September 20, and it is also mentioned that this is probably when " the 3.0 like merge window is likely to close." Don’t know how Spectral Cycles X is doing but if we are still not ready I guess we can wait for 3.01 3.1 or something (not sure about the version naming in 3.x series). (Just checked the previous blog post, next version is 3.1)