AMD has recently made a change to allow RDNA 3 and 4 users to use their media framework (AMF) alongside the open source Vulkan driver RADV.
However, this means that RDNA 1 and 2 users who wish to develop code for the framework (mainly for use on windows), are left high and dry.
Despite this, the change has been experimental for quite some time, with the last driver for RDNA 2 (25.10) containing SO files that provide the same functionality. The following takes these SO files from the newest distro available (REHL 9.6), unpacks them, and moves them to the users usr/lib folder for any ARCH based system.
This works in my testing, allowing me to run the sample programs on the AMF repository, however, as time goes on and both mesa and the kernel changes, your results may vary.