I will try to put it simply

1. the linux kernel provides the hardware compatibility in a general sense.
2. Then the driver for your specific card is coming as a kernel module, in your case amdgpu, which is the open-source driver that works very well, but amdgpu-pro is the proprietary driver from AMD and most NVidia users will also install the proprietary module.
3. Finally you have libraries implementing APIs to OpenGL, Vulkan, video decoding, etc. All of those are bundled in software packages, that depend on your distro. In your case you can most certainly install a MESA package that will give you everything you need, compatible with the Kernel you have.

In summary, drivers come in 3 parts: Linux kernel, kernel module, libraries. Usually you install a driver that provide you the module and libraries compatible with the kernel. You rarely have to worry where they exist on the filesystem, and nowdays most distro will automatically detect and install what you need.

Ok, no that simple in the end 😅