Which heating system and how to combine it with photovoltaic / solar thermal?

In my opinion, the brine heat pump is over the top for new builds. The air-to-water heat pump does its job, and you save a lot of costs for drilling, etc. The cooling is also nowhere near as good as air conditioning. I would rather invest the difference between the brine heat pump and the air-to-water heat pump in the largest possible photovoltaic system and an air conditioner. In summer, when you need the air conditioner, there is electricity anyway.