Preparation for photovoltaic or solar thermal with air-water heat pump

If a heat pump is used as a heat generator, I would always choose a photovoltaic system instead of a solar thermal system.

Exactly. A solar thermal system requires a correspondingly large storage tank, which you actually don’t want with a heat pump and would also be inefficient. Directly using photovoltaic power for heating is also nonsense because it is uneconomical when you can convert 1 kWh of electricity into 2-4 kWh of heat via the heat pump.

Install empty conduits for the photovoltaic system and that's it. Solar thermal system eliminated.