@poshook You EFI folder was a mess! Here is my change log:
1. Removed the APPLE folder with firmware updates.
2. Removed things in your TOOLS directory that weren't in your config.plist, Openshell.efi wasn't OC0.8.5, it was an older version. Changed to current.
3. Fixed your platform ID's in the config list, you had iMacPro and MacPro listed there, like you used 2 different configurators to add them.
4. Updated your original config.plist, and made 2 others config-rebuilt.plist (cleaned up version) config-rebuilt x299.plist (made to mirror a x299 system on Dortania setup).
Your config plist was conflicting with the SMBIOS that was in there twice but with different data. You should look at it in ProperTree line by line.
As
@Feartech said your USB mapping is missing from your EFI folder. Mapping is required after MacOS 11.3.
You can download the Catalina install from Apple as described in the Dortania setup manual. Free download!
Hope that this helps you, it'll take some testing. Now after looking at you EFI files, I would definitely get a SATA drive or a WD SSD (NOT Samsung) to use as a test or backup install to test OpenCore EFI changes. That's what I do.
I know you can do it, and move forward don't get discouraged, Check BIOS settings. The Big Sur x299 thread has great info on the AsRock x299 motherboards BIOS settings and sample EFI's too...