This is a simple door catch that you can reconfigure via Onshape to meet your desired measurements. I'm using it outside to hold the door to my shed open. Once opened, no force is exerted on the part to prevent deformation over time. The bulge prevents the door closing, but also allows it to be easily pulled away.

I originally printed this with a thickness of only 2mm, but there was very little stregth there, leading to this update to parameterize the part so you can easily alter it.

The model version can be copied here via your OnShape account:

https://cad.onshape.com/documents/1d413b9fcba269f0af053954/v/62a679e4ccc3d63a3cd5f4ae/e/dfc69aaf43f5bfeda4d7775a