This 3u rackmount model can hold 3 1u items.

Maybe an bit over created and quite big but this is to be sure it hold your switched and or gateway in my case UXG Pro.

If you want to use cage nuts make sure to give a little sand down on the flat side so the glue can hold it better.

glue the cage nuts shown on the picture havent tried other glue than 2 component epoxy this sits very strong and can handle some force.

Give the file an play around with some settings walls or infill but make sure it has to hold some weight at the wall side so i wouldnt recoment going below 15% infill and 3 walls