This is not guide…. just my repo of the EFI for Opencore… but feel free to use it, if it suits you…..
I5-8400 Coffee Lake
NVME samsung 970 500gb
WD SSD 250gb
NO CFG unlock in BIOS
Big Sur 11.1
One minor ACPI error (I dont even bother to fix it)
Fill in PlatformInfo in config.plist