It can depend a lot on your definition of "ready to use". For instance, a common threshold for "ready to use" is "included in a released version of the upstrea

It can depend a lot on your definition of "ready to use". For instance, a common threshold for "ready to use" is "included in a released version of the upstream Linux kernel, and not under CONFIG_BROKEN or CONFIG_STAGING". Under that definition, neither ZFS nor bcachefs are "ready to use".