I think this xTool pen are so incredible! (Ballpoint Pens with Stylus (12pcs) https://www.xtool.eu/products/ballpoint-pens-with-stylus-12pcs?variant=50008359338197) They are made of a soft material like rubber and beautiful colors. At the end there's a tip you can use for touch devices. Very easy to engrave.
xTool provides a library for material parameters.
The parameters I selected are tested on a M1Ultra 10W.