I got there in the end, but tbh, the endgame was a bit of a dreary slog with the endgame. There was an Enigma Variations-themed puzzle not so long ago where the time went not on figuring out what to do (the fun part) but on doing it, and with the risk of minor errors making it impossible without starting over. This was a bit similar.
Also the final part of the endgame was somewhat superfluous - another 1/2 hour of repeated Googling just to find a not particularly interesting detail on the theme. Not my favourite.