Because I think this is basically bug 1965882 but we've never had it reported on an AMD system before so don't yet know the solution.
The above is only for when you're sticking with the 'nouveau' driver. But as mentioned in comment #3 and again in comment #10, we recommend you install the proprietary NVIDIA driver instead.
Please try adding kernel parameter:
amd_iommu=off
Because I think this is basically bug 1965882 but we've never had it reported on an AMD system before so don't yet know the solution.
The above is only for when you're sticking with the 'nouveau' driver. But as mentioned in comment #3 and again in comment #10, we recommend you install the proprietary NVIDIA driver instead.