Small case for this nice display.

It may be a little tight, I had to sand down the PCB by a few tenths of a millimeter all around. I replaced the spacers provided by Waveshare by plastic ones with M3 thread and used a nut to fix it. When mounting the display you might need to bend the case side to get it into. Rear side is simply pushed in.

Works for me; next time I would add some space around the display (to avoid sanding), add 2-3mm in height and width (for more easy mounting) and create the small mounting plates with rounded corners.