Is the rubber coating on your Logitech MX Master 3 falling apart?

Then this replacement shell is exactly what you need. Simply rip off the rubber coating across the whole surface of the mouse and attach this replacement coating with some thin double sided tape. This model is based on Rikkarlo's work.

This is much simpler than printing a whole replacement shell since it's only the rubber coating that gets replaced.

For best results print with a 0.2mm nozzle at 50% speed.