Which heating system for the new building (prefabricated house)

We signed the purchase contract for our house last week; all 5 FH providers had planned an air-to-water heat pump. In the end, we bought a KFW 40+ house with photovoltaic, controlled residential ventilation with heat recovery, a house without a basement from a smaller provider in solid wood in Upper Swabia, whose overall concept absolutely convinced us - also price-wise. The heating is executed with ground heat baskets and a corresponding heat pump without an additional heating element. The air-to-air heat pump or air-to-water heat pump has the worst efficiency when the heat demand is highest; there are also very different experiences in the forum regarding energy demand and COP. I would definitely not do it without additional heating, especially not in cold regions.