I feel sorry for whoever has to read and understand the solution. It looks like the typical convoluted unreadable mess I see the models generate for software. It might be technically correct, but gaining insight from it is just intellectual hell.
There's an opportunity to build a Lean "optimizer" which automatically simplifies existing proofs.
Skill issue. Also lean is meant to be executed, not read.
There's an opportunity to build a Lean "optimizer" which automatically simplifies existing proofs.