GNU/Linux Ubuntu 18.04 Installing Radeon RX 7900XT/7900XTX Driver Guide
Hi! The linked Tutorial shows you Step-by-Step How to Install AMD Radeon RX 7900XT/7900XTX Graphics Driver in Ubuntu 18.04 Bionic LTS GNU/Linux 64-bit Desktop.
And there are 2 Radeon RX 7900XT/7900XTX Ubuntu Bionic Graphics and GPU Driver available Alternatives: the AMDGPU Pro and the AMDGPU Open-Source.
The AMDGPU Pro Software includes Support for Accelerated Graphics, MESA Multimedia, Pro OpenGL, Pro Vulkan and Pro OpenCL.
AMDGPU Driver supports all AMD Radeon GPUs based on the Graphics Core Next (GCN), Radeon DNA (RDNA), and Compute DNA (CDNA) architectures.
Finally, for the Radeon Open Source Drivers See instead: How to Install AMDGPU from Ubuntu PPA.
AMDGPU Ubuntu 18.04 Installation Guide