The default audio output device does not switch automatically on Fedora 35. For example if I plug in an HDMI cable the output device remains 'Speakers - Built-in Audio ’ in settings.
What I think is worse, the device remains blank in settings after unplugging the cable and I have to click on the dropdown to select the builtin speakers once again.
Sorry, I had to clarify this is a clean install. This appears to be a bug indeed. I really doubt that it is an intended change. I submitted a bug report just now.