This happened to me with a brand new mb air. Got stuck after following the steps I have taken in the past to complete a **** and pave which, to my surprise, is not even close to the same steps with an Apple laptop with an M1 chip and Big Sur.
First, to get into recovery mode, you have to shut down the device, and then to turn on, hold down the power button until you see the option to continue with recovery mode. Cmd+R or Cmd+Ctrl+R doesn't work anymore.
Next, if you get yourself to the point that you are reinstalling Big Sur and get the “No users available for authorization” problem, have no fear. Delete the Macintosh HD partition and the Data partition. Granted, your experience after that is going to be somewhat messy. Eventually you will need to get back into recovery mode and disk utility, and create a new partition Macintosh HD. Otherwise, Big Sur offers to install, but there are no available HDs to select at that step. You must create the new Macintosh HD partition after deleting both Data and Macintosh HD.
I find that the previous answers to this question were insufficient in terms of details. There was no guidance regarding the creation of a new partition before reinstalling Big Sur.