See, the openness is one reason I'd lean towards Intel ARC. They literally provide programming manuals for Alchemist, which you could use to implement your own card driver. Far more complete and less whack than dealing with AMD's AtomBIOS.

As someone who has toyed with OS development, including a working NVMe driver, that's not to be underestimated. I mean, it's an absurd idea, graphics is insanely complex. But documentation makes it theoretically possible... a simple framebuffer and 2d acceleration for each screen might be genuinely doable.

https://www.x.org/docs/intel/ACM/