first you need to check if your graphics card is correctly detected and if the drivers are running normally on your system. To do this you can use these commands:

lspci -v | grep -i vga 

This will display the device that has been identified as a graphics card by the system

lspci -k | grep -A 3 -i vga 

This will display the graphics card and the loaded drivers for it.

Now in case the commands show you that your graphics card is not working you can visit the official AMD website

https://www.amd.com/en/support/download/drivers.html

search for your hardware, download and install the Debian package using the following command

sudo dpkg -i amdgpu-driver.deb

if the drivers still do not work, you always try to change the Kernel version by following this guide:

https://linux.how2shout.com/how-to-change-default-kernel-in-ubuntu-22-04-20-04-lts/

I hope this helps your issue.