Something that comes to mind (ha!) as a method to try that might allow you to still do art, even really good art, would be just to lean into that apparent lack of coordination. Like, ok so your hands refuse to translate what you see in your mind's eye? Cool, let your hands lead the way. You can just leave it at that and just do freeform scribbles, that would still be artistic, even if you're not happy with the result. But you could also take it a step further and try to make it a sensory feedback kind of thing. (There's a term for it, but I can't remember--I have a bunch of brain issues too.) When your hand does something your brain didn't want it to do, pause and remake the picture you had in your mind's eye to incorporate that "error" such that it becomes the new picture in your mind's eye. Then try again with your hands until they once again do something else you didn't intend, even if that happens immediately. Just repeat that process. Incorporate the unintended into a new intention. This not only has the potential to make artwork you're truly happy with, even if it will never be photorealism or anything beyond your personal brand of abstract art, but it can actually help train your brain to get better coordination.

Sorry if I'm suggesting something you've already thought of and tried, I know it's not exactly groundbreaking, and can even just be considered a basic common practice for someone who is, say, beginning to learn to draw. But for me at least, thinking it out like that, and consciously, repeatedly shifting my intention while allowing and being accepting of "mistakes" has lead to the creation of things I'm sincerely proud of, it has gotten me closer to achieving the kind of brain-to-hands interface you describe that we both wish we had, and has just been rewarding in general.