Kernel panic won't boot

After a failed disk erase, I restarted the computer and now it won't go past the "your computer restarted because of a problem press a key or wait a few seconds Mac" kernel warning. I have tried all sorts of recovery mode command options and sometimes it shows the apple logo for a second and then goes back to the warning text. After a few loops the circular with a line through it (the prohibitory icon) shows and then the computer shuts down. Can't get past this stage.

iMac 27" late 2014.

OS: Catalina.

Was working perfectly until I tried the disk erase to prepare to give away the computer.