I just solved the error "No users available for authorization." which occurred upon attempting to reinstall Big Sur on MacBook Pro with Apple M1 chip. Likely what happened when you went to Recover Mode Disk Utility you did not erase all the volumes of data. Within Disk Utility go to View Show All Devices and select "Container disk" and erase. Then close out of Disk Utility, and now you should be able to reinstall Big Sur. Something to note is that it's possible that erasing container disk will fail - this happened to me. I turned off the laptop and tried again, and it worked. Good Luck!