We would like to inform you that Cocktail (Big Sur Edition) will be delayed and will not be released before or on a same day the final version of macOS Big Sur will be available for download.
We are waiting for the Golden Master version of macOS Big Sur to be released before we will start to develop Cocktail (Big Sur Edition). This is simply because Apple is making so many changes to this operating system in every beta.
I'd say
Catalina macOS 10.15.6 is pretty much a "finished" product.
Edited to reflect a bit of sarcasm.