What BIOS Version are you on?
The correct layout ID for this board is 7. So that would be alcid=7. It should already be set by SSDT-ASUS-Z490.aml but adding the boot arg for AppleALC.kext wont hurt. My front panel audio works as expected (Switches between internal speakers and headphones when headphones are plugged or unplugged there) and no static sound (all the outputs sound good and work).
Whatever green must be adding some device properties or frame buffers that are needed by your DGPU. My 5700XT doesn't need much to be recognized and load drivers. SSDT-X16-GPU.aml is very minimal compared to other ACPI injections I've done for my old GPUs in other systems. I've never played with a R9 280.
If you want to use just the SSDTs that are distributed by the developers of OpenCore, just use the ACPI folder from the USB installer and update the config.plist to use those SSDTs. I'd still recomend using everything else from the Internal Boot Drive folder. You can learn more about SSDT-ASUS-Z490.aml by opening the .dsl file I included in the main folder in MaciASL.app. Notes are colored green. If you haven't carefully read the guide, you may want to.