Comparison of groundwater / brine / air heat pump

From that I conclude that the decision is not easy and depends on the framework conditions.

It will probably also depend mostly on your preferences. You can read for days and in the end you will realize that the diesel recommends his diesel and the petrol engine his petrol engine. In the end, they are all right because the car gets them from A to B.
It’s the same with heating; they all provide warmth and each has advantages and disadvantages.
The question is more about what best meets your requirements, whether you are the type who doesn’t want to deal with it at all or someone who wants to engage with it more deeply, etc.

The suggestion with the gas connection wasn’t serious this time, was it?

Of course it was serious, I am absolutely sure of that, because here you will find many users who heat reliably, cheaply, and comfortably with it; those are circumstances that not every heat pump owner is granted :D.
maybe you have a preferred technology, then you will also find supporters and helpers for it; those exist for every heating technology.
Note: "Links" are forbidden here, there will be complaints.

Heat pumps are still very expensive and often prone to faults.

Nevertheless, the heat pump is currently the most installed heat generator in Germany. Not bad for an expensive and fault-prone technology.

@TE: Don’t listen to Bookstar. He’s just pissed off about his own (poorly designed) heat pump heating system ;-)

The heat pump is currently the most installed heat generator in Germany. Not bad at all for an expensive and error-prone technology.

Yes, but only thanks to former subsidies, KFW target achievement, and CO2 penalty tax. Certainly not because of the solid technology :D

Certainly not because of the solid technology :D

Why should a principle/technology that has been used in air conditioning technology (in air conditioners) for decades suddenly no longer be solid?

Why should a principle/technique that has been used for decades in air conditioning technology (in air conditioners) suddenly no longer be solid?

Because the technology that has been used in series production for over 100 years still does not work properly. That is why it is also applied, for example, to clothes dryers and vehicles, in order to have even more test fields. And the approximately 14 million devices (heaters only) installed in Europe since the mid-90s are still not enough to finally eliminate all the mistakes of heating engineers... That's how it is with pointless technological gimmicks. Just marketing nonsense, nothing else. *Irony off*

Then a modulating one where baFa is eligible.

So a cop of 4.0 has

BaFa requires min > 4.5!?

From an economic point of view, according to the current state of technology and funding opportunities, the air-to-water heat pump would probably be the winner!
And 140 sqm are certainly well warmed even by the smaller ones. Especially since these, as mentioned, are becoming more efficient year by year and are now where brine-to-water heat pumps were 5-10 years ago.

In principle, I have been a fan of brine-to-water heat pumps for 20 years, but for the current house, I was convinced to go with the air-to-water heat pump. See the above pro arguments.