GNU/Linux Manjaro Installing Radeon RX 6900XT/6950XT Driver Guide
Hi! The linked Tutorial Shows you Step-by-Step How to Install AMD Radeon RX 6900XT/6950XT Graphics and GPU Driver in Manjaro GNU/Linux 64-bit Desktop.
And there are 2 Radeon RX 6900XT/6950XT Manjaro Driver available Alternatives of AMDGPU: Proprietary and Open-Source.
The AMDGPU Pro Software includes Support for Accelerated Graphics, MESA Multimedia, Pro OpenGL, Pro Vulkan and Pro OpenCL.
So for the Radeon Open Source Drivers see: How to Install AMDGPU.
GNU/Linux Manjaro Radeon RX 6900XT/6950XT Driver Installation