It turns out Bcachefs is still being developed and its primary author, Kent Overstreet, continues to believe it can compete with the likes of Btrfs and ZFS as a next-generation Linux file-system.
A Phoronix reader pointed out this weekend that there's now a Bcachefs initiative on Patreon. Kent mentions there that he is still working on this file-system by himself full-time and talks more about Bcachefs advantages and how he views it as superior to other Linux file-systems.
According to Overstreet, Bcachefs is stable, it's fast, it has a small and clean code-base, and it has the necessary features to be a modern Linux file-system. Of other Linux file-systems, Kent says that Btrfs was designed too quickly and has many design mistakes that make it problematic and it's taken far too long to stabilize. Of ZFS on Linux, Kent feels that ZFS will never be a "first class citizen on Linux."
Check out that Patreon link if you are interested in more details about the latest state of Bcachefs.