Finally got this working on my Intel NUC 9 Extreme KIT with Unraid 6.9.2
IGPU 630 UHD => LibreElec
GPU Nvidia GTX3060 => Windows 11
Steps: Separating the HDMI audio device from an IOMMU group was necessary. (used space invaders video specify the vfio-pci.ids below). Then added all in the boot config in the flash drive like this. Especially important seem to be to add this part : i915.alpha_support=1 video=efifb:off,vesafb:off modprobe.blacklist=i2c_i801,i2c_smbus,snd_hda_intel,snd_hda_codec_hdmi,i915,drm,drm_kms_helper,i2c_algo_bit
config:
kernel /bzimage
append initrd=/bzroot pcie_acs_override=downstream vfio_iommu_type1.allow_unsafe_interrupts=1 vfio-pci.ids=8086:a30e,8086:a348,8086:a323,8086:a324,8086:15bb i915.alpha_support=1 video=efifb:off,vesafb:off modprobe.blacklist=i2c_i801,i2c_smbus,snd_hda_intel,snd_hda_codec_hdmi,i915,drm,drm_kms_helper,i2c_algo_bit
finally found this vbios which works for iGPU somewhere (was referred to), see attached. I could not dump it myself due to io error.
Then installed Intel drivers in Windows etc. (Had Splashtop Streamer installed first..).
Amazing community and especially amazing Spaceinvaders videos made it possible :))
Thanks everyone!!
vbios_gvt_uefi.rom