Heating (Heat Pump) Incorrect, heat output too high?

And when everything is optimally set, you continue and, for example, block the heating at night for 12 hours because it runs more efficiently during the day. And then it only delivers on average 3kW of heat and cycles less.

I agree with you on everything else, but blocking the heating at night or setting a setback is now proven to be nonsense because of the inertia of the screed.

It's not about classic night setback but about the lower outside temperature at night and therefore worse efficiency than during the day.

Exactly. The thermal mass in the house is currently being used to bridge the low air temperatures at night as a source for the heat pump. This only makes sense with an air-water heat pump, when using photovoltaics during the day, with significantly oversized heat pumps to reduce frequent cycling, or conversely with cheap night-time electricity.

Otherwise, you are right, tomtom79, night setback makes little sense in modern houses.

But the OP is not quite there yet ;-) First, take care of the basics..