To be fair the ASUS DSL-AC88U has been around for ages now, but I avoided it due to the initial high cost & it's buggy firmware.
I borrowed one a while back, but no matter what settings I entered or what firmware version I ran I couldn't get multicast to work with BT TV.
It seemed to be a bandwidth problem, SD feeds ok, HD feeds stuttered & UHD pictures were just a green mess, all worked fine using BT's router.
I think many manufacturers think G.Fast is a bit of a damp squib so they are looking to FTTP as the next big thing, skipping releasing G.Fast models altogether.