Using Fedora 34 KDE Respin, kernel-5.13.14-200.fc34
After unplugging an HDMI cable, the entire USB interface is disabled.
All 4 ports stop functioning (except for charging) until I restart the computer.
Needless to say plugging in the HDMI cable results in no kernel or usb events from udevadm or dmesg
The camera and microphone can disconnect and reconnect just fine though.
Anything specific in the journal when you unplug? What happens if you restart udev (e.g. systemctl restart systemd-udevd)? Keep in mind you may have to restart PipeWire or Pulse if you restart udev, since their audio autodetection may get screwed up (basically, don’t get worried if you lose sound, since you can just restart your audio subsystem and things should just work).