Here is a version I designed for the resulting POOPs. On the Anycubic Kobra 3 Combo, two screws are embedded on the side of the printer below the POOP ejection (in the carrier frame): My solution consists of two parts: You attach one part to the printer frame with the two screws. The second box is then placed inside the attached box. This keeps it firmly mounted, and at the same time, you can easily remove the box with the POOPs.

For larger projects with many color changes, you will have to empty the box more often; the volume is not enormous, but it looks nice, is flush-mounted, and smart. Everything printed with a 0.20mm nozzle and 20% infill