I can tell you one thing myx3090 with backplate block is 2.7Kgs.... none of those toys that are attached to pcie slots can help you they bend or warp because of their length either buy the flag thing or find your own way but def dont buy that long plate I've got 3 of them that came with various gpus they never worked even on a lighter 1080ti

that wee need this kind of supports is a sad truth, i guess we will welcome 1000w gpus one day