The fact that AdaFruit is selling SeeSaw based rotary encoder boards (and the SeeSaw repository has a board definition folder for a 4-rotary encoder board with a commit comment of “hey its working!” dated 3 months ago) would indicate that your information is stale. I wasn’t trying to sell AdaFruit products, rather show an example of your front panel microcontroller implementations.
Also looking at the repository, I think it looks like that SeeSaw is currently only targetted to samd µCs, so if one isn’t into samd µCs then this might not be the project for you. Though, if one can legally handle GNU GPL source code in one’s projects, SeeSaw might be a viable starting point for what ever shenanigans one is up to.