Probably going to need your EFI buddy (just the config is fine). It technically works OOB if you apply a simple patch. Running 19,1 isn't ideal, iMacPro1,1 is a far far better smbios to run. You will see much better performance and stability. You even get proper power management for your CPU which isn't a huge deal but still. You need to run CPUfriend if you're on 19,1 or 7,1 (MacPro).
If you do move smbios', make sure to disable your iGPU. You'll need an extra reboot afterwards to go back in and set up the dGPU parameters. Also resetting the NVRAM is a must, but you may also want to take this opportunity reset your CMOS. Garbage in there can interfere with a hardware change. Moreover, follow this guide to clear out any cruft left over from the smbios transition:
https://www.tonymacx86.com/threads/guide-clear-multiple-configuration-identities-in-macos.256316/
All you need is the latest Lilu and WEG and it should work. I'm running the exact same card without issue.