USB Worked OOB.
Everything you need is in the Dortania guide. You'll need an SSDT for B550 though, https://dortania.github.io/OpenCore-Install-Guide/troubleshooting/troubleshooting.html#stuck-at-acpi-table-loading-on-b550
Here we have the AMD OpenCore kernel patches for macOS Big Sur. These patches will boot macOS versions 10.13.x, 10.14.x, 10.15.x and 10.16.x (11.0.x)
We've stated these as Experimental as they could break between beta updates of macOS. Currently though they have worked since Public Beta 1...
Been using an AMD hack since 10.6... Never owned an Intel machine. Between my Athlon II X2 215, FX 4300, Ryzen 5 2400G and now my 3600 I've had every version of macOS since 10.6 installed. Moving from Enoch to Clover and now to OpenCore. Been using OpenCore since AMD support was added to it.
Nice to see you've adopted the change but not to be discrespectful, there's no need to your "tools" on AMD. An AMD hack is a learning curve. No one learns anything from clicking stuff in an application and having no idea what it's doing.