For AMD dGPU you should have the
latest versions of Lilu + WhatEverGreen installed, I find it always best to download the latest release versions from the git hub project pages - see this guide for links and more info :-
An iDiot's Guide To Lilu and its Plug-in's Last Update: 22nd Jan 2021 (Add note about OpenCore config.plist modifications) About this Guide Note: This guide was written when Clover was the boot loader of choice as such the config.plist examples in this guide are mostley Clover specific ... if...
www.tonymacx86.com
As P1LGRIM suggested make sure to remove all AMD/Nvidia inject/fake id options in your config.plist and let WEG do the work as it does a much better job than Clover.
Ensure you remove any and all references to Nvidia ...
If you previously had the Nvidia WebDrivers installed be sure to uninstall them, check /L/E for any left over Nvidia kexts, if there are any then you should delete them and rebuild the kext/kernel caches. Do Not touch anything in /S/L/E.
Cheers
Jay