I believe that the issue might be that the amdgpu driver is too new, judging by this string of errors:
Dec 20 21:30:54 minion xserver-wrapper[1080]: (II) AMDGPU(0): [KMS] Kernel modesetting enabled.
Dec 20 21:30:54 minion xserver-wrapper[1080]: (EE) AMDGPU(0): [drm] Failed to open DRM device for pci:0000:05:00.0: Invalid argument
Dec 20 21:30:54 minion xserver-wrapper[1080]: (II) AMDGPU(1): [KMS] Kernel modesetting enabled.
Dec 20 21:30:54 minion xserver-wrapper[1080]: (EE) AMDGPU(1): [drm] Failed to open DRM device for pci:0000:05:00.0: Invalid argument
Dec 20 21:30:54 minion xserver-wrapper[1080]: (EE) Screen 0 deleted because of no matching config section.
Dec 20 21:30:54 minion xserver-wrapper[1080]: (II) UnloadModule: "amdgpu"
Dec 20 21:30:54 minion xserver-wrapper[1080]: (EE) Screen 0 deleted because of no matching config section.
Dec 20 21:30:54 minion xserver-wrapper[1080]: (II) UnloadModule: "amdgpu"
Dec 20 21:30:54 minion xserver-wrapper[1080]: (EE) Device(s) detected, but none match those in the config file.
Dec 20 21:30:54 minion xserver-wrapper[1080]: (EE)
Dec 20 21:30:54 minion xserver-wrapper[1080]: Fatal server error:
Dec 20 21:30:54 minion xserver-wrapper[1080]: (EE) no screens found(EE)
So if this doesn't end up working, I'll definitely look into the pinning thing, because 5.10 seems like my best shot.
Figured I'd do the pre-setup before I went to bed, so I've run the grep command and put the board_name from that output such that the patch now reads thus:
Exciting! Thank you so much for your help mate, it's very much appreciated.