I have an ARCHER AX 10 and RE505X both of them support wifi 6 and onemesh but I can't understand why the RE505X does not support backhaul ethernet, plus the wifi 6 deco is way to expensive. 

In my oppinion RE505X should have backhaul ethernet because it have wifi 6, and also cost up to 120$ ( the most expensive model). It expensive enough for the developers to support backhaul ethernet. About other range extender, is ok to skip this feature because they are cheap.

Thank you