So yeah, you seem to be getting the general idea...
And you lost it. There's other blocking issues here and there,
yes but the big one glaring at us in the face at the moment is the fact that you still need to reimplement the kernel features. You still seem to not understand that neither AMD nor Intel provide us with kernel drivers. They don't. I've looked into this. So no matter what, the people in FreeBSD maintaining the graphics stack have to play persistent game of catch-up with Linux - Linux releases a new kernel with new merged AMD/Intel code, and we have to reimplement that. Which may be trivial or not. I'm not a graphics developer, so I am not sure.
And you seem to be stuck on AMD. AMD sucks on FreeBSD. Use Intel or Nvidia. I've never had a single AMD card work properly *and* perform well. I've had the former, never the latter. I blame AMD's crappy GPU and CPU architectures, as of late, and their complete and utter disconnect with the gaming community. Nvidia may not be open source friendly but the hiccups they've given are zilch. Ditto for Intel.