Devin Montes posted a custom camera filter kit for creating shapes in bokeh.
https://www.myminifactory.com/object/3d-print-custom-camera-filter-26987

The design was wonderful and I thought I would just make a basic lens cap out of it. It prints in one piece and you sort of snap it apart. I have had good luck with resizing this in tinkercad, while maintaining the height at 6mm. Seems to work well for me. I have printed this in PLA and PETG. Both work well.