There's been a proposal for Fedora Linux to become a new Fedora immutable variant and now it's been approved by the Fedora Engineering and Steering Committee (FESCo) to happen for the Fedora 39 cycle.
While distributions like Fedora Linux have been using Dbus-Broker for years already as their high performance D-Bus compatible implementation to, for Ubuntu 23.10 later this year is finally where it looks like Ubuntu will be transitioning to this better alternative to dbus-daemon.