First of all, my notes are completely written in English.
I wrote my personal notes from Algebra Platzi course in Gitbook (collection/space).
I synchronized my GitBook space with GitHub repository (from GitBook to GitHub).
When I modify this content, I will do it in the GitBook space, and then I will sync it with the GitHub repository. But you will be able to make suggestions for content modifications on GitHub.
GitHub repository (ALGEBR21001): https://github.com/ddasilva64/ALGEBR21001
By the way: I only use Notion as CMS for projects.