Hello Johannes,
approach the matter without using your head and trust your body feeling. Visit model homes of the providers. Spend a longer time in a closed room. Sometimes in a smaller room, sometimes in a larger one. Windows are closed. You will notice that the houses feel different. Take your impressions seriously for a decision. Technically, many things can be told to you and there are indeed several really good concepts. You will live in your house and no one else. Do you like to sleep with open windows and can the technology handle that? Take that seriously.
I find many of the energy-optimized heating systems to be "stuffy." My eyes (burn because of dryness), ears (feeling of pressure), and respiratory tract (slightly irritated) do not like that. Why should I build something like that even if others say it is right and better?
Certainly, energy costs are an important factor. But saving money and as a result feeling less comfortable is, in my opinion, an unfriendly prioritization for life. Be self-aware.
Regarding photovoltaics: From my point of view, solar energy is a gift. Just accept it. The system pays off sooner or later. The battery usually helps shorten the payback period.