After reading this thread and bz 2123998, I had thought that the Fedora 37 mesa packages retained accelerated video for open codecs (for AMD hardware). However, the Fedora wiki[1] indicates that even open codecs are no longer accelerated without third party packages. Is that true? (I don't think that I can test this, since I don't have any AMD GPUs, only Intel.)
1: https://fedoraproject.org/wiki/Firefox_Hardware_acceleration#Configure_VA-AP...