Questions about Gardena Micro-Drip-System Basic Unit 1000

Is it possible to buy only the end piece (the screwed-on part with the attachment for the black hose)? This attachment keeps breaking off, and then I have to buy the whole thing, which is actually nonsensical.

25mm

Are both adapters available with this base unit 1000, i.e. 4.6 mm and 13 mm hose adapter?

I have a 3/4" underground pipe and would like to connect this pressure reducer to it. Does anyone know which adapter I need for this? Or is it only possible via the 1/2" garden hose?

On my basic unit, a strong narrow jet of water sprays out of a small hole on the side for quite a while after the watering time has expired. I haven't noticed this before, so I don't know if it has always been like this. So my question is: is this normal or do I have to get a new basic unit? Merci very much in advance!