Vesa plate with slots for magnets, add a pause in print to drop in the magnets.

Hardware: M4x8mm: 4 M4 nut: 4

Magnet Size: 10mm x 5mm x 2mm

Below is the project share on OnShape, should be able to change it to any magnet size needed by editing.

OnShape project link: https://cad.onshape.com/documents/bcf529cb2467d3fb28d83f69/w/8db830ef71ecb6ef32a37d02/e/407a44d27c2999aa4e91a136