I stopped looking at your debug files after seeing that you have not customized the config.plist with your own serial number / IDs. You can't simply copy and paste the config.plist I provided without customizing your own serial number and other IDs. Please copy the config.plist from the EliteDesk800 archive that I attached to Post #1 in this thread and make sure that the XXX-MASKED-XXX values are set to your own values. You can use Clover Configurator to do this.
EDIT:
@tkmanutk Note that I had a bug in one of the config.plist versions that I posted. I had inadvertently "masked" the Board-ID when I was sanitizing the config.plist for public posting. Please use the latest config.plist that I have included in the EliteDesk.zip archive attached to Post #1, because it has the correct Board-ID for the MacMini8,1.
EDIT2:
@tkmanutk The config.plist that you posted
here has a bug that I introduced in an earlier version of the config.plist that I posted. I had inadvertently deleted the framebuffer value AAPL,ig-platform-id in the posted version. It wouldn't surprise me if this missing AAPL,ig-platform-id was causing the problem you saw and why you don't see the problem with a newer version of my config.plist.
I apologize for my screw-up. This thread is still a work in progress and I have not yet converted it into a guide. Using the material I post in this thread is going to require a degree of knowledge and experience to check my work.