1008f after deleting volumes on Mac mini 2018 A1993. I have reset PRAM, SMC, I have removed from ICloud. Still getting 1008F

I had loaded big Sur on to my MacMini 2018 A1993. I had deleted the volumes to prepare for sale, when I have come to reload, via internet recovery, I get 1008f, I have removed the macmini from the iCloud account, I have reset PRAM, I have unplugged to reset SMC. But still get 1008f, I have tried to create a bootable installer for El Capitan from an old Mac, but I can’t get the Mac mini to recognise a bootable USB, I can’t get it to start in anything except internet recovery. Any ideas?