Adobe doesn’t do GPU Red debayer as well. It’s strictly done in CPU. Mercury engine just speeds up the rest of the render. Nobody is allowed to do R3D GPU debayer. It’s kinda ironic, because, there are no technical reasons for that, as Red Rocket itself is a GPU device. I know of at least one company, that did try a crude GPU debayer of R3D and without any optimizing of the code was able to achieve 18 FPS. Nevertheless, Red owns R3D and they are free to set any policy they wish. And they choose to sell Red Rockets…
On the other hand, ARRI RAW GPU debayer is allowed…