Check the position of the [LOCK] switch. And, check the menu setting to see which controls that it disables.
Apologies for the extremely late response. I wound up not sending it in when I originally planned to due to some unexpected shoots and a trip to NY. Luckily, the RF lens I was using I could set the forward dial to change the Aperture setting on the move, so that was extremely helpful.
The following is what I found out from Canon when I sent in mine for repair just last week:
The camera body is covered under warranty the first year only.
The cost of replacing the part out of warranty is $429 US.
I have a Platinum CPS membership, so that's 30% off, coming to a total of $300.30 US.
The camera is also covered under the Canon CarePAK. So in the end it didn't cost me anything, and I got it back within 5 days easily - repaired and working again.
09/26/2023: New firmware updates are available.
08/18/2023: Canon EOS R5 C training series is released.
07/31/2023: New firmware updates are available.
05/31/2023: New firmware updates are available.
05/18/2023: New firmware updates are available.
03/30/2023: New firmware updates are available.