This bracket supports the GPU by bolting to the back of the GPU and the bottom of the NR200 case. 

I designed the bracket for my RX6800 reference, but I think it should also work for the RX6800XT, RX6900 and RX6950XT as they seem to have the same size cooler with the mounting holes on the back. I've seen other reference cards also have the mounting holes so maybe this will work for those too, leave a comment if you try!

It mounts to the GPU with 4x M3x20 bolts and to the bottom of the case with 2x fan screws. 

There are two sets of holes integrated for routing a cable tie through the bracket to secure PCIe power cables (see photos)

With the bracket installed the GPU will be mounted very solid and doesn't move at all, so it's safe to transport.