I recently built a project that I installed in an electronics box, https://a.co/d/2Kn5OQk, I wanted to be able to put it on the front of my pellet smoker using magnets.

This design uses the existing mounting holes and screws. There's places for 4 magnets on the back. I ended up printing two of these, one for the top and one for the bottom. The top has 4 magnets, but I only used 2 in the bottom. The box is held securely in place.

These are the magnets I used. https://a.co/d/c8xK21x They're really powerful. You have to be careful when working with them. Put the mounting tape in the holes first. Then stick the first magent to the mounting tape. You can then push sideways on the rest of the magnet stack and slide them to the next mounting hole. If you try to take the magnets a part and place them one by one, they will be attracted to each other and get pulled out of your hand. If for some reason you still need to do them individually, I learned that if you put some duct tape over the magnet holes after you install them, then it's easier to get the next magnet in place.

This model may fit on other electronics boxes. The bump-outs on the bottom will determine if it'd work.

Print the model with the magnet holes facing up. I had to use supports inside the bolt holes.