Mac Mini 2018 Reboot Loop

I have a newly acquired Mac Mini 2018 that cannot get out of reboot loops.

I’ve already formatted the drive using target disk mode and trying to install a fresh copy of Mojave. There is nothing to restore or backup at point. I’ve tried:

1) resetting pram and nvram

doesn’t make any difference just reboot loops

2) making a bootable usb using the Apple Mojave install image and terminal instructions

the usb can be read, I boot holding down Apple key. The option will be given to install Mojave, once I hit enter, it doesn’t take me to MacOS utilities, it reboots and continues to loop

3) use internet recovery to install OS

i can successfully enter internet recovery mode, hardliners Ethernet. the progress bar goes to the end in about 5 minutes and instead of entering the installation program, it gets into a reboot loop and will restart in internet recovery mode and start the process all over again

4) hold down d during boot to get diagnostic mode

this doesn’t do anything. I don’t know if this is because the drive is clean. I can hold down Apple D and it will take me internet recovery and then restart loop.

5) hold down shift during boot to safe mode.

this doesn’t work because there is no OS on the internal ssd

6) install Mojave on an USB and hold down Apple to boot, I can get the drive to appear but hitting enter will just restart instead of trying to load the OS

any ideas? Is this computer a lemon?