Thank you for the bday wish!
I'm glad you got UHD 630 to work. I'm wondering if my issue with it was because I hadn't fully reformatted my EFI partition prior to running the second install. I'll leave that be since my new install seems to be rockin' with the GPU added into the mix.
I'm now attempting to do post-installation and I'm confused in a section for the iMessage fix. Inside SMBIOS, when I click the magic wand, I don't see iMac18,3 on the drop down menu. iMac18,3 is our System Definition correct? I'm assuming this is the case because that's what it reads under Model Identifier in System Information and also it's what I'm seeing in SMBIOS when I load up the config.plist. Anyways, my issue is that I'm wondering, how am I supposed to generate a Serial/UUID's without using my correct System Definition?