Heat pumps require a lot of energy and make noise

Where can I see what flow rate the heat pump produces?

In the heat pump. You just have to check the menu. Were the heat pump and the reading/adjustment options explained to you at all – pump performance, flow/return, heating curve, etc.? When defrosting is happening at my place and about 1,800 liters/hour rush through, I can also hear it slightly. In normal operation like now, it's 800-900 liters/hour and everything is inaudible (even without a bypass valve).

No, nothing was explained to me there, my heating engineer was already shocked that I was even in the service menu and said if I change anything there, eventually nothing will work anymore. But in the normal menu, you can't do anything, not even adjust the heating curve or the flow temperature. You can only set the optimized temperature, etc. But yes, when it is defrosting, it is also extremely loud, but only the pump, my noise comes from the HKV. Maybe I'll still find something about it, compressor fan. I've noticed that too, it runs at 100 percent during defrosting.

Could it be that the feed pressure is much too high? When I listen with my ear to every floor, I hear proper noises. This makes me wonder if too much is flowing through and therefore the high consumption? How do I adjust this?

Is it really just a pure water sound or are compressor vibrations/transmissions being transferred to the house?
Do others hear the sounds in your house as well or only you?

When I turn off the valve at the distributor so that no water can flow anymore, everything is quiet. The noise wouldn't necessarily bother me, but my girlfriend has huge problems with it and already wants to move out.

I think I and many others could help better if you answer questions more precisely.