The Autopen AF is a commercial product for this.[1]
There's also MAXWriter and RealPen. All have paper feeders, so they can turn out page after page, unattended.
In China, some kids use automatic writing machines to do their homework.
See also the LongPen, conceived by author Margaret Atwood for remote book signings. I particularly like the name because it sounds like something out of her fiction.
In China, some kids use automatic writing machines to do their homework.
[1] https://youtu.be/3FHGO2i0bL4