I'm not sure if extending the Einsteind notation made this much more readable than what it is supposed to be replacing.

It doesn't help that I've read three pages of the docs in an attempt to understand and all of them just rely on examples with no real explanation.

If the best explanation of your custom notation uses examples of the supposedly less readable language it is not more readable.

Edit: Turns out there is an explanation of the notation, but it is a bit burried. I would strongly recommend skipping the first page of the tutorial.

Main repository, https://github.com/fferflo/einx

Literal strings of programming language code inside a programming language are a symptom, and rarely a good solution.

Related - einops https://github.com/arogozhnikov/einops