Typo - meant RT-AC68U.
Have tried it both wifi and wired. The comment above about non-merlin on the node is interesting. Will have to try that.
It's about the only thing I've not yet tried.
I have spent three days now trying to get two RC-AC68U's to aimesh.
It flat out doesn't work. Tried it wireless, tried it wired, tried every single trick in every single post on this website. It never sees the node to add it.
I'm basically baffled and out of options, and these units are about...