GNU/Linux Mint 20 Installing Radeon VII Driver
How to Install Radeon VII Driver on GNU/Linux Mint 20.x Ulyana/Ulyssa/Uma/Una LTS desktop – Step by step Tutorial.
And there are two Mint 20 Radeon VII Graphics Driver available Alternatives: the AMDGPU Pro and the AMDGPU Open-Source.
Moreover, the AMDGPU Pro Software includes Support for Accelerated Graphics, MESA Multimedia, Pro OpenGL, Pro Vulkan and Pro OpenCL.
Especially relevant, the Latest Driver supporting a Device varies over Time, so before the Setup you should check: AMD Radeon Drivers Support
Finally, for the Radeon Open Source Drivers on Repo See instead: How to Install AMDGPU from Mint PPA.

Installing Radeon VII Linux Mint 20 Driver
How to Install Radeon VII Driver on Linux Mint