This was also my first thought - it reminds me of some Matrix based note taking apps. See the Matrix blogs at https://matrix.org/blog/category/this-week-in-mat

This was also my first thought - it reminds me of some Matrix based note taking apps. See the Matrix blogs at https://matrix.org/blog/category/this-week-in-matrix/ https://matrix.org/blog/category/this-week-in-matrix/ to see how these projects have been progressing. I think there is space for another paid competitor also built on Matrix!