These are my OC files to boot the latest Big Sur release using a Ryzen 5 3600 with a supported AMD GPU. Everything seems to be working fine except iServices, check this out to make them work. IOUSBHIDDriverDescriptorOverride.kext is needed in order to get working some TKL keyboards that do not work with mac os out of the box.
Complete build:
Ryzen 5 3600
MSI B450 A-PRO MAX (Realtek 8111H)
SAPPHIRE R9 380
Samsung 970 Evo SSD
New AMD kernel patches require you to add your CPU's CoreCount before you can boot your system. Currently, these patches are configured to work with a 6 core CPU (ryzen 5 3600) but if you own a CPU with a different CoreCount you should check this before trying to boot with my OC folder.
This was achieved thanks to the people at https://dortania.github.io/OpenCore-Desktop-Guide/