I have a finicky dryer vent connection that I needed to be able to access to secure, and also to open up and clean, and the easiest way to access it was to cut a hold in the drywall. So, I made a 20cm x 20cm hole, knowing that this was slightly smaller than my print bed, and then like 4 months later I finally came back and designed and printed this frame and removeable panel cover so it could look a little nicer than the paper tower I had taped over the hole previously.

The frame is secured to the drywall using two small pegs you slide in after printing.
The panel is secured to the frame using 8 small magnets.

I've uploaded the fusion and step files, so you can customize the opening, frame thickness, magnet hold sizes, or anything, as needed for your opening.