Which type of heating system in the new building?

Price-performance ratio is gas very much ahead. Air-water heat pump also good, but prone to errors and requires a lot of adjustment work. If gas line is available, then gas. Otherwise air-water heat pump.

Gas line is far away (see above) How exactly is it prone to errors?

I think geothermal energy, with its high initial costs, is still something for enthusiasts who always need something special. There are many arguments in favor of air-water heat pumps. Only one argument remains for the gas boiler: its sophistication, operational reliability, and immunity to misuse. It runs smoothly and trouble-free often for over twenty years; the pumps simply cannot achieve that.

What is better with geothermal energy? In winter you don't have to heat electrically but what about otherwise?

First of all, in our lowland regions you don't have to heat electrically in winter at all. That should be the absolute exception (normally from -10 to -15 degrees, if at all).

But geothermal energy provides consistently good consumption and can also cool better (please forget about an air-to-water heat pump for cooling, then plan for air conditioning). However, it is quite a bit more expensive (drilling). But with larger plots, a shallow collector can also be used.

Passat is good, E-Class is better.

And Ford Fiesta never in the workshop.

And Ford Fiesta never in the workshop.

I always called my Ford Fiesta Ford Fiasco. That thing was only ever in the workshop in the end. :(

For your information only: There was a somewhat longer thread here about half a year ago, which dealt with electricity costs. To my recollection, the average annual electricity costs with these heating devices were higher than the average annual gas costs. However, I do not know whether photovoltaics played a role in that. But feel free to search for and read through the thread yourself.