Hello,
It come from the linux-firmware update who get regression for AMD GPU
Remove your grub options and try to downgrade :
sudo apt install linux-firmware=20240318.git3b128b60-0ubuntu2.26
then mark linux-firmware as hold
sudo apt-mark hold linux-firmware
apt-mark showhold #you should see linux-firmware in the list
the regenerate initramfs with the good firmware :
uname -r #your actual kernel should be the output
sudo update-initramfs -u -k 'the result of uname -r'
sudo reboot