fix the problem
sudo nano /etc/default/grub
add this arguments on 'grub cmdline linux default     radeon.si_support=0 radeon.cik_support=0 amdgpu.si_support=1 amdgpu.cik_support=1 amdgpu.ppfeaturemask=0xffff7fff
save and type sudo update-grub.
add rx5500xt to the first pci expres as default video out.

If this method does not work, I have implemented a mining os for amd cards. I can give it to you to try.