Construction costs are currently skyrocketing

Interest rates do not rise/fall to my knowledge with demand. Demand has certainly not decreased significantly in recent weeks.
The articles I have seen online so far all still predict rising interest rates. However, I have not fully understood why...

In my opinion, higher interest rates should lead to lower construction activity and thus lower demand. An apartment as an investment with 30% equity is simply no longer profitable beyond a certain interest rate.
In the long term, building prices should also fall again, but the war and the disrupted supply chains, which existed even before the war, still play a role here.

Currently, we have rising interest rates, extremely rising raw material prices, a chronic shortage of skilled tradespeople, and a government that is restructuring the subsidy program (and probably does not want to support single-family houses in the long term at all).
It is a conceivable difficult situation.

For example, apartments in Munich were already "extremely" expensive 15-20 years ago. Today, one would be happy to have a paid-off apartment in Munich, which is certainly worth double to triple.
Unfortunately, the current situation can only be properly assessed in the future.

Interest rates are short-term more aligned with bond yields. And yes, they are rising massively. But nobody. I do not know a single person who knows! knows what it will look like in 12, 24, 100 months

The further into the future, the higher the forward premium. That's probably what he meant. You are basically buying protection. Currently probably the right decision, but no one has a crystal ball.

Well, about the same time last year I still thought: what is going to happen meanwhile that interest rates will rise. After all, the economy has to flourish, and that works very well with low interest rates.

Interest rates to my knowledge do not go down/up with demand.

… exactly. They rise in times of crisis. At least that's how I've always somehow understood it. Someone once told me here that I have always built, bought, and financed in periods where the yield curve compared to the next 3-5 years was always going down. So I have financially messed up my life planning :p

Well, last year around the same time I was still thinking: what is supposed to happen while interest rates are rising. After all, the economy has to flourish, and that works very well with low interest rates.

I thought exactly the same 1:1!!!

Interest rates will rise. Even the current interest rates are still historically low. The market has been flooded with money in recent years. That was (and is) a reason for the still immense demand for home ownership. Debt costs too little money. The now relatively high inflation will also lead to higher interest rates: fewer people will be able to afford home ownership - so demand will decrease. Theoretically. However, there are dozens of other factors: supply, price developments in the construction sector, population development, key interest rate trends, alternative investments (or rather the returns of these investments), and so on and so forth. It certainly will not get easier...

Do you think that despite the low key interest rate, interest rates will still go higher?

Let's put it this way, the key interest rate is already at 0.0%: it can't go any lower (otherwise you would even get money for your loan!) Your mortgage interest rate, however, consists of the sum of a) refinancing costs of the bank (approximately the key interest rate) plus b) individual risk premium (depending on borrower, loan-to-value ratio, location) plus c) cyclical risk premium plus d) profit margin. a cannot go lower, d hardly can (due to the market environment). After 10 years of booming economy, b can hardly be reduced any further. That leaves point c. How do you assess the environment: energy, sanctions, war, supply shortages, inflation expectations, pandemic aftermaths, etc.? If pessimistic, then this will eventually affect point b) as well in feedback. So you really have to be quite optimistic to expect mortgage interest rates to remain at the same level!

I am of the opinion that none of those present here will ever again see interest rates below 1 percent in their lifetime. The low interest rate phase has been passed, and it will never return. Realistically, key interest rates should be at 6 percent and mortgage rates at 8 percent. Anything else contradicts all economic principles. Due to artificially low interest rates, we have seen bubbles in various asset classes and a phase of extreme indebtedness of states, companies, and private individuals. Along with this come supply shortages and inflationary price developments. And I fear that the external constraints from a monetary policy perspective make drastic and rapid interest rate increases unavoidable. Inflation, especially that of food prices and energy, will become a threat to the political class. The pressure on central banks to rein in inflation will increase significantly. We are currently seeing how the USA tries to calm its voters. The USA has quietly increased its import of Russian oil by 40 percent while Europe is pushing for an oil embargo. Likewise, under pressure from American farmers, the import ban on fertilizer from Russia has been lifted again. Yes, the Americans continue to get fertilizer from Russia while we no longer receive any. There, it is about damage limitation. And with us, the damage keeps getting bigger.