Installed AlGrey's Vanilla config.plist and recommended kexts onto the EFI partiiton.
Booted the SSD from the OEM Mac to make certain all was working. Completed setup process.
Then booted SDD from Threadripper 1950x into Clover with flawless startup into Catalina.
My only complaints are lagging speed during use, ethernet and audio kexts not working. Used a USB dongle with ethernet to connect to WWW and update some apps.
Threadripper lags with Mojave as well but not at all on High Sierra.
Will continue to test and will clone Catalina to another SSD to rule out possible issues.
Asus Prime x399-A
Corsair 32G Vengeance LPX