Unfortunately, the fitting does not have an SVGW number. I will inform the responsible department of this.

Yes, you can unscrew the mixing nozzle of the kitchen tap to descale it. - Unscrew the mixing nozzle clockwise, ideally using a pipe wrench with plastic jaws to avoid scratching it. - After unscrewing, you can place the mixer nozzle in a solution of vinegar or citric acid to dissolve the limescale. - Leave the solution to work for around 10-15 minutes and then rinse the parts thoroughly with clean water before refitting the mixer nozzle.

Unfortunately, there is no information about the thread of the water outlet. The following reducer may also need to be purchased https://www.galaxus.ch/de/s4/product/neoperl-reduzierung-sanitaerinstallations-zubehoer-5850194.