For manufacturing you will need disk-shaped neodymium magnets, 3mm in diameter, 2mm in height.
In the photo there is an option with six magnets, but now it seems to me that the option with ten magnets works better. The attachment contains both options.
The model is printed upside down; supports are needed to print the cutout (see photo).
It is advisable to print with PETG and 0.2mm layer height.
I am attaching CAD models in STEP and f3d format, so you can easily change the model to suit your needs (remove the cutout, change the number of magnets, etc.)
The author marked this model as their own original creation.