according to freshports drm-kmod has two dependencies:
1. gpu-firmware-kmod>=20220511 : graphics/gpu-firmware-kmod
2. drm.ko : graphics/drm-61-kmod
So you were installing one of the two dependencies. Looking at the first one, in turn depends on 127 others.
Short of it, it becomes too much of a dependency burden for what you yourself described as a headless FW appliance. These dependencies are for desktop type systems.
So my suggestion is to see if you can build it or pull the package into a VM and see if you can then move it across.
1. gpu-firmware-kmod>=20220511 : graphics/gpu-firmware-kmod
2. drm.ko : graphics/drm-61-kmod
So you were installing one of the two dependencies. Looking at the first one, in turn depends on 127 others.
Short of it, it becomes too much of a dependency burden for what you yourself described as a headless FW appliance. These dependencies are for desktop type systems.
So my suggestion is to see if you can build it or pull the package into a VM and see if you can then move it across.