That is very odd. So PC00 works, but modifying it to PCI0 doesn't work? When left to PC00, the WiFi card works with functional WiFi?
I've further updated my
repo to include the RX580 as a Slot-1 impl. and moved the 5700XT to the Slot-3 impl. Both load fine and I've further corrected the audio naming for both as you can see in this screenshot. In my prior screenshot, the audio interface is listed separately but was not named correctly.
Edit: Relating to the OP of Thunderbolt implementation, I have modified KGP's SSDT to conform to this motherboard and have working TB3 as you can see in the screenshot below. The two USB-C ports in his SSDT were named SSP01 and SSP02 whereas the DSDT from this motherboard reports them as SS03 and SS04. Correcting that lists the USB-C controller under PCI devices as well.
View attachment 448276