The “handle pipe” on my Nilfisk Aero 26 had small cracks in it that caused the hose to coupler to come loose. This clamp holds it together. I used a m3x16 screw to fasten it.
If you need a new hose coupler, @Lindh3D has made one: https://www.printables.com/model/617870-nilfisk-hose-coupler-replacement (compare with your original one, Nilfisk has different versions that look very similar).
Depending on the properties of the plastic printing with a brim can be a good idea. My first print failed due to warping.
Printed with PETG (https://www.prusa3d.com/product/violet-transparent-petg-filament-1kg/), Prusaslicer, filament setting: Prusa PETG, 0.2mm structural, 100%infill.
The author marked this model as their own original creation.