So with the recent drama it looks like bcachefs isn’t going to stay in the kernel for too long. What do I do now? I have my root filesystem as bcachefs on multiple devices. Is it possible to migrate to btrfs or ext4?
There’s no need to jump into conclusions when it’s too early to tell.
If later, it so happens it gets removed, and you don’t want use out of tree stuff, which is still possible through several means, including building your own linux (your own kernel), then you can back all contents of your partitions up, create new partitions with the FS of your preference (ext4, btrfs, whatever), and finally copying over the contents of that last backup. No need to stress out this early, :)