Tested with my WD3 Premium, but it may work with any Karcher hose with the same style of tip.
Several versions with angles (45° and 90°), inline (short/long), and the parametric Fusion 360 file to modify it as you wish.
Careful, the short version let the hose go past the screwable mount.
It's the one I printed because it was going to a piece of 21mm plywood with a 35mm hole in order to hold the tip.
Resolution: .28mm
Infill: 20%
Filament: Dailyfil PETG Black
Notes:
You will need support for the angled ones.
The author marked this model as their own original creation. Imported from Thingiverse.