Heyo disqard -- thanks for the feedback! You can actually already do something like this.
From readwise.io/export there is a bulk markdown option which lets you save all of your highlights/notes in a zip file, with one markdown file per document.
Automating this via a kind of folder sync is not something we do yet, but could be cool! We do have an api that makes it really easy to pull out all your highlights/notes too readwise.io/api_deets#export