Edit may 7 2020: Added a hole where the screw is, noticed it was preventing the mount from being flat on the frame. shortened the leg on the inside so the rail inkeep is not covered.

This is a camera mount for the ender 5 and the Logitech c922. But it can be used for every 20x20 printerframe and actually doesn't have to be at a corner.
Other cameras with a similar base fit too! The camera base is 42 mm wide at the printer side (front) and 40 at the back. It is 50 mm long on the right and 64 mm long on the left side.

The belt is cut out of the design so it won't interfere.
Mirror this if you want to mount it on the left side, it should be the same.

I recomend at least 20% infill to have less chance at camera wobble and make it sturdy.

I suggest printing this with the camera platform facing down (touching the bed).

Fusion 360 file can be provided. I am not a professional designer, this is good enough for me and probably for some other people too.