And after many failed attempts I was able to put an end to it.
I added the kernel parameter:
amdgpu.dcdebugmask=0x10
… and it’s gone, for good!
In the specific case of Endeavour OS, using Dracut and systemd-boot, I added that parameter to /etc/kernel/cmdline to make the fix permanent. If using GRUB, you need to append it to /etc/default/grub instead.