Hi here is an EFI folder with the latest Opencore release (0.5.9) with everything working including Boot-Chime, proper port Mapping and HotPlugging/Swop for external hard drives. You may have to have an additional entry for your RX 5700, I don't know. I have included a modified BIOS from Gigabyte that has a CFG Lock/Unlock feature in the BIOS Menu.
1. The first thing you need to do is to format a spare USB drive as Fat32 then drag and drop the file 'AZ390WUK' onto the usb drive you just formatted.
2. Reboot the machine into the BIOS reset the machine to Optimised Defaults (or words to that effect) by pressing F7 save and reboot with the USB Drive attached to a known working port.
3. In the BIOS you need to invoke 'Q-Flash' (can't remember which F-Key at this point but sub menu will tell which one)
follow instructions to transfer the file from the USB Drive to update the machine's Bios.
4. When the copying is complete, remove the usb drive and the machine will reboot. Press the delete key to boot into the BIOS once more and check the BIOS version has changed from previous.
5. Now setup the BIOS for OpenCore, you will come across the CFG Menu to toggle it Off/On. You're now ready to try the EFI Folder I attached also. You will need to enter your personal data to the config.plist, do not use Text Edit, use Xcode or better still, use PlistEdit Pro. Good luck.