I finally got around to trying out the vfio-pci-override script. I added my device ids and placed it in the boot directory, since I suspected that it tries to read the file before the booting??
Funny enough - nothing happened after adding the file “hook” in my mkinitcpio.conf file. Looking at @Janos’s vfio.conf modprobe entry, I added the relevant lines there. Once that was added, I got the same behavior as before - a broken frame buffer, but still able to enter in my encrypt pwd and boot / bind normally afterwards.
I reverted back to what I had before. BUT someone updated the Arch forum cross-post of this issue saying they added the relevant driver BEFORE the vfio hooks. I’m going to give that shot real quick…
UPDATE - that worked. I added “amdgpu” before the vfio hooks and the prompt came back (after a second long black screen as it switched to using the igpu). Seems like a decent workaround for the time being