Let there be more speed:
something around 150-180stich/min, huge leap forward after thinking less microstepping ---> more speed.
Now everything is public to download
https://www.thingiverse.com/thing:3216283
So, what is what and how does it work?
Sewing machine part is any old or new sewing machine. Only change for original is stepper motor with synchronised pulley system (chain/belt drive) and more embroidery friendly presser foot. It is recommended to use older sewing machine, way more convenient to mount stepper motor to cast iron and prises are relatively cheap.
XY movement consists mainly 3D printed parts, 12 pcs and similar parts known from self build 3D printers. Both axes use GT2 belts, nema17 steppers and both directions are fully scalable.
Synchronous movement comes from Arduino powered GRBL G-code interpreter, it is mouthful, but basically machine moves using G-code send to Arduino. It is not that complicated and it is only carrier like any other one when going from system to another one.
Now we have movement and code, but how to make nice shapes and export to G-code. It is nothing to do with medieval sorcery, it is a matter of downloading Inkscape
https://inkscape.org/ and extension called Inkstitch
https://inkstitch.org/
Help and examples how to use Inkstitch extension can be found address above. End result should be really close to hobby level embroidery machines, just slower speed. After all, embroidery machine is nothing more than overgrown sewing machine.
More details and build instructions
https://inkstitch.org/tutorials/embroidery-machine/