I think it's more comparable to GPU naming. 40XX gives me the generation, and the XX part (e.g. "4060"/"3080 Ti", etc gives me relative the performance within that group. Except instead of something informative, Apple just goes with an arbitrary word that means "the best."

which makes the name redundantly uninformative! So why not make the differentiating technical spec part of the name, or have something similar like M2 XXXXX where XXXXX is the number being comparable?

It still has some value. It indicates a group of product.

Non-sequential naming also gives them the flexibility to shift new products into the category over time. They do this with the M1/M2 in the iPad.

Because that's what the others are doing with their i6-12345B and it makes even less sense than three simple names anyone can memorize in two minutes.