Brank I'm not interested in the RP aspect, but it is still a nice puzzle by itself. Plus you learn a bit of history and how the Enigma worked in principle. What the creator thought was a strength and what ultimately lead to Poland and the UK cracking it.
Since this message doesn't use the plug board and is likely written in English we could probably brute force crack it if our imagination fails us. I.e. try combinations until "TH" appears often or the amount of "E"s and "T"s is high. At the moment I have generic source code for the Enigma that simulates how the wheels rotate on each key press and what path the current takes from an input letter to an output letter. Pretty much what the web versions do. But we could pre-compute all the internal states for a given set of wheels and ring positions - i.e. the internal state - and end up with a super fast instant-enigma to try different initial letters in the rotor windows). It would use ~14 megabytes of RAM and almost no CPU once built.