Just checked your motherboard's CPU SUPPORT LIST and there are no BIOS updates for the 5xxx Series Processors: ASRock > Fatal1ty X470 Gaming-ITX/ac
So your new processor is a paper weight temporarily until ASRock comes out with a BIOS that supports the new processors as mentioned by Earnhardt in his previous reply.
If you need to have the computer up and running until a new BIOS comes out then borrow or use a Ryzen 1xxx, 2xxx or 3xxx series processor that is listed on the Motherboard's CPU SUPPORT LIST.
The only Motherboards that support the new Zen 3 Processors are the 5xx series motherboards that has BIOS support at this time. Next year the 4xx Series motherboards will have BIOS support.