Hi,
that’s the same issue as the thread referenced by the following post:
Cause:
Your AMD graphics card is more recent than the AMD driver shipping with the latest Ubuntu 24.04 LTS at the moment, as the graphics card was introduced after Ubuntu’s April 2024 release date. The included AMD X-Video driver can’t handle the card fully.
Solution: Run XOrgConfCreator(1) for expert mode, and answer “Use advanced settings?” with yes and “Use modesetting driver …?” with yes and select the created xorg.conf via XOrgConfSelector, then logout and login.
This switches from the outdated AMD specific X-Driver to the generic modesetting X-Driver, which can deal with your graphics card.
See the full referenced thread for thoughts about Ubuntu 26.04-LTS and further background info.
-mario