Update to this design, thanks to customer feedback on Etsy, I was able to enlarge the bottom air passage holes, and added a hole in the top to try and blow dust and smoke off the laser diode lens itself. I am including my cad file so you can modify it if need be to work on your application.

A air assist nozzle I designed for my atomstack a5 pro, has room to get a qtip up the center to clean the lens. This is designed in American imperial, but prusa slicer does convert it automatically for metric.

Print with PETG or better filament for high heat deflection, use painted supports as you don't want supports inside the air passage