Netgear Nighthawk X6 R8000 will not attempt update firmware to OpenWRT?

Hi there! I'm new around here and I was hoping to flash OpenWRT on my Netgear Nighthawk X6 R8000 router but when I attempt to flash OpenWRT from the CHK file here:

It just stated that the firmware file was incompatible and redirected me back to the firmware update page and doesn't even attempt an install. Might my router have the wrong chipset or something? Do the new Firmwares not allow installation of OpenWRT, or is it detecting some incompatability I should be wary of when attempting a firmware flashing by means other than an ethernet cable? How do I begin to troubleshoot this?

Thanks for any help!