Attached is the EFI I use for my GA-Z170X-UD3. I am using a Sapphire Pulse RX 570 Graphics card. It is running Big Sur. The USBPorts.kext limits the number of USB ports to 15. You may have to try them to see which ones I disabled.
Sleep, audio work. I use speaker output, but both of the monitors I have connected are selectable in sound preferences so I assume that HDMI sound works too.
MLB, ROM, SystemSerialNumber, and SystemUUID in config.plist-> PlatformInfo -> Generic have been deleted. You should use yours or create new compatible entries.