This isn't the basis for a theory, personally I don't see any reason to think Ricken or Devon aren't as they seem.

Just finished my third watch, and I still find it really jarring how someone as apparently well-adjusted, empathetic, and intelligent as Devon would get together with a certifiable imbecile like Ricken...

Again I think the pairing is just plot convenience or to facilitate the (excellent) comedy we get from Ricken. But anyone else feel like Devon could do a whole lot better? Unless I am missing some whack theories 👀