It down to interpretation. I interpret "There will be no clues" as in....This will be nothing like the rift mystery. There will be no in-game beacons telling us to "go here, go there". The codex gives us clues, in some way or another. If it doesn't, then we might as well close this thread and go back to hauling freight between systemsI'm not convinced that Raxxla is obfuscated by anything as simple as a cipher on the Codex (and honestly, I'd be hugely disappointed if it was).
We were told there would be no clues, and yet here we are, trying desperately to find clues.
I am not suggesting that a simple cypher will be the answer. I am wondering if a simple cypher will give us a piece of thread to pull.