Monoprice has the wire gauge as standard text on all of their splitter products. It doesn't mean that a different or smaller AWG won't work; they are just trying to cover their bases with the safest option. I have no proof of this but I highly suspect that they do not for the possibility of...
I have a early HDMI receiver from Denon and it's held up quite well but Atmos looks like the first real new thing in quite some time. Would love an upgrade.