The average wait time in Germany to get a heat pump installed is more than 1 year.
It is very difficult to even get someone to come out and give you an offer since most of the heating companies know that they cannot deliver anything for a long time.
Then there is the issue that most people have older houses over hear. That means standard radiators for the vast majority of houses and no underfloor heating.
Most heat pumps only get the water up to 55 - 60c, which is not really hot enough unless you have underfloor heaters or very large radiators.
There are a couple pumps on the market able to get to the 70 - 75c range, but they are very new, very expensive and very, very limited in their availability.
It will be at least 10 years before most houses have switched from gas/oil to heat pumps.
Especially when you consider that up until about 5 years ago, the government was giving massive incentives to install new gas systems. I personally did this and have no interesting in spending another 20k,
One could imagine that in 10 years the German government will change course again and fuck everyone that just spent money on a heat pump. Germany likes to pretend they know best, but from my experience, the government here is even more incompetent that most.