refer to post

For my Asrock Z490M-ITX I found this workaround for getting HDMI to work:
In the EFI/OC/Kexts section add:
”FakePCIID.kext" and "FakePCIID_Intel_HDMI_Audio.kext"
and declare them in the Kernel/Add section ("FakePCIID.kext" before "FakePCIID_Intel_HDMI_Audio.kext")
Still in the config, in the
DeviceProperties/PciRoot(0x0)/Pci(0x1f,0x3)
section add:

device-id | Data | 709D0000

For this result:

hda-gfx | String | onboard-1
layout-id | Data | 31000000
device-id | Data | 709D0000

After a restart, your HDMI device will be in the Audio options.
It seems that using Layout-id 51 (33 -> Hex) (Asrock Steel legend)
eliminates a problem with the Front Mic (Hissing) which
is present with the default 49 (31 -> Hex) Layout-id.
(Credits to @Lorys89 and @Jolly of MacOS86.it)