[SUCCESS] RX 6600 XT with working DRM on Monterey 12.1 Beta

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https://preview.redd.it/i4is9rif94y71.png?width=1524&format=png&auto=webp&s=a9b4be2562dc6ce0f958f83ae995c464d7ab27c5

Using a dGPU-only SMBIOS to not bother with the weaker iGPU.
iGPU was disabled in the BIOS and also DeviceProperties->Add in my EFI doesn't contain any entries as these are for the iGPU only.
You have to use WhateverGreen in RELEASE mode and have agdpmod=pikera in your boot-args.
The rest is as explained in the OpenCore guides.