I've created "High Sierra" installer pendrive with Unibeast, and replaced all files at EFI partition by the ones of DenOfLore zip file (CLOVER, BOOT, APPLE and Windows folders, I don't know the purpose of most of them honestly).
What issues do you have? I have the Coolermaster H500M Case, so the USB.kext will not work the same for you...Can You share your EFI with me, please.
This my build:
gigabyte z390 master
sapphire nitro+ radeon vega 64 8GB
ballistix sport 32 GB 3600MHz