Imac will not; Boot, nor start Disk Utility or Recovery mode
Hi
I have a 2013 27" with 32GB ram and wanted to do a factory reset and went into the disk utility and deleted the Macintosh HD, it's a hybrid disk with a combined 1,2GB, and something went wrong and it wanted to restart.
When restating there is no chime like normal and the apple logo is only there for a second, then it comes to a screen saying 'your computer restarted because of a problem press a key or wait a few seconds' and then it restarts again and keep looping like this.
I have tried to enter disk utility mode and recovery mode etc. but nothing happens. I have tried Command+R, shift, option etc etc etc - nothing.
I have a USB with a Catalina install on it connected, but as it will not enter disk utility I can not select it.
What can I do? How can I get access to either disk and get the new install on the way?