Delurking for a moment to express how I’m always impressed by the things this community figures out. I'll try to contribute with something I noticed: the key to the code epigraph (itself another Diagram epigraph, reproduced below), suggests that it may not be the desolation itself brought by Surgebinding (As Nalan and some others think). Rather, it’s the effect of Taln breaking after millennia of torture.
(Small note, The Desolation is a bit oddly personified in this quote.) Combined with some passing mentions in the Second Letter (“millennia have passed without Rayse taking the life of another of the sixteen”, “an equilibrium reached”), the timeframe suggests that in the present state of Roshar (Honor is dead/broken, no Surgebinders), Odium remains impotent in some way. Exact dates are, to my knowledge, still fuzzy. So it certainly seems possible that Surgebinders can do something (Heal something broken? absorb Voidlight from the sphere? No idea. Note this may also suggest a reason Hoid, who is presumably aware of certain things, is encouraging refounding of the Radiants) to assist/free Odium, and allow him to rampage again through the Cosmere (or possibly also be killed for good?). If the Knights Radiant eventually realized/were told this, that could definitely be something that leads to the Recreance (would also be very anti-journey-before-destination). Or it could be the KR did mistakenly believe they were causing Desolations (being the “fools” of the epigraph) or were actually causing desolations, though that’s a bit less intriguing (and less consistent with the Diagram, so this is predicated upon how much you trust/interpret that). The Herald/Honorblade/Oathpact (all but Taln breaks their oaths) and Radiant/Sprenblade/Recreance (all but 1 order break their oaths, though I think it's not the Stonewards) parallels are also interesting to ponder in this respect.