Thanks for tracking this down! I have the same issue on FW13 Ryzen HX370, using Ubuntu 25.04 with X11 (I disabled Wayland for reasons, with WaylandEnable=false in /etc/gdm3/custom.conf) and was pulling my hair a bit. Using kernel 6.14.0-15-generic; if any of that helps.
I updated /etc/default/grub with:
GRUB_CMDLINE_LINUX_DEFAULT=“quiet splash amdgpu.dcdebugmask=0x610”