I found this in Fedora Devel lists : https://fedoraproject.org/wiki/Changes/DefaultPipeWire. I made a try. All goes fine except that plasma-pa and bluedevil have been removed because of pulseaudio dependency. Rebuild the packages with something like : (# if fedora > 33 Requires pipewire-libs ) help me for a use of plasma-pa mixer. Is there a solution for this issue in next rawhide builds. Thanks.
FEDORA-2021-29d7d49890 has been submitted as an update to Fedora 33. https://bodhi.fedoraproject.org/updates/FEDORA-2021-29d7d49890
FEDORA-2021-29d7d49890 has been pushed to the Fedora 33 stable repository. If problem still persists, please make note of it in this bug report.