+1 For the "Everything Works" build. Just finished using as a guide to get my new Asus Z390-I/9900K/RX580/32GB system (iMac19,1 SMBIOS) up and running.
I migrated everything over from my 3 year old 6700k build to a fresh NVMe disk, and then used ModMikes EFI setup as a base EFI setup.
The only issues that I have had was Dell 1560 BT/Wifi card that I ordered from the Amazon link in first post (a bit expensive IMO), and WiFi worked but no Bluetooth. Installed Windows as well after scanning through the posts here and still no luck.
Swapped that card out with the similar Lenovo card that I ordered from Ebay for ~$18 and it immediately worked in macOS. Before I put the system, which is now just sitting on the test bench awaiting its new case to arrive (Ncase M1), I'm going to try to swap back to that Dell card to give it one last try before trying to return it.