Made something similar a while back Kindle-send[0] to send blogs to my Kindle. It also uses readability under the hood.
Now I use it to send blogs, books and sometimes send whole archives of a website (you can use it in scripts).
You can export Kindle highlights to Obsidian, so one benefit of making these epubs is how you accumulate the highlights at one place.
Although, name is kindle-send but it can send to any ereader that uses email as a mechanism to send books.