The “nozzle” part of the pump supplied with my eSun vacuum kit split. I tried to glue it, but it didn't hold, so I spun up a design for a replacement in FreeCAD.

It's not perfect (I'm not a FreeCAD expert), but it works.

Be sure to use an outer perimeter of 0.4mm, or it might not fit.

The example in the photo was printed using PETG with 0.24mm level height.