Finally got around to finishing the game, mostly out of curiosity for how it would end.
After wasting time trying to get to Mon in Gray's playthrough, I just looked up what to do. Wound up looking up many of the answers in the DIS section, not because I think I couldn't have solved them, but rather because I wasn't sure if becoming voided would impact things negatively. At that point, I was pretty done with the game wasting my time. It ended up not mattering since Bee takes all your locusts anyway, and I didn't want to attempt a deathless run of that fight.
One thing I don't really get about the DIS fight...why is the weakness the right bit? Was there supposed to be a clue about this somewhere?
Overall, game does some cool shit, but it's so mired in forced repetition (made worse by the fact that the game is happy to force you to start over). And as far as puzzle games go, this feels closer to Fez than Outer Wilds/Tunic.