Construction costs are currently skyrocketing

no, see the footnote. That is the rate of change compared to the same quarter of the previous year. The 8% in 2022 means 8% more than at the same time in 2021. Anything above 0 is more or less further increases. I also find the graphic rather a bit confusing.

Please correct me if I'm wrong, but according to my reading, the new construction prices have risen by a total of 8% from 2001 to the peak in 2022??? And in 2023, new construction is 4% cheaper than in 2001?

I correct that because it is wrong. The zero line stands for the slope of the function of the price changes, not for the absolute prices. It is read as follows: from 2001 to 2022, prices have (almost) always only risen. In 2023, they have fallen for the first time (except for new construction). Of course, it is still significantly more expensive in 2023 than in 2001. The other two graphs actually show absolute comparisons. The first one only shows relative changes in %.

Just be a little patient. Those who have equity now or build it up in 1-2 years will see that there is still something possible. The market regulates itself after all, at least in extreme situations.

I am here in NRW and when I look at the funding program of the NRW.Bank for social housing, I have to conclude that today you have to invest 10%, which for example would be 150,000€ for a small multi-family house, to receive 400-500k in funding a year later. The ROI is amazing, you can do it three or four times and then flee abroad. But shh. :)
A little tip for the bros whose test centers no longer operate.

Especially in the daily press, EON has published the new prices for the basic supply - including [Baustrom]... It goes from 33.68 to 46.80 gross as of 1.6... Carryover effect hooray...

Can [Baustrom] also be obtained elsewhere or is one always tied to the basic supplier here?

Especially in the daily press, EON has printed the new prices for the basic supply - so also construction site electricity... It goes from 33.68 to 46.80 gross as of June 1st... Transfer effect hooray...

Can construction site electricity also be obtained elsewhere or are you always bound to the basic supplier here?

We were also able to get the construction site electricity from another provider. I simply concluded another contract with the new meter number.

Just in the daily press, EON has published the new prices for basic supply – including construction power... It goes from 33.68 to 46.80 gross as of June 1st... Follow-on effect, hooray...

Can construction power also be obtained elsewhere, or are you always tied to the basic supplier here?

I connected it at the neighbor's. Of course, this assumes a willing neighbor (with a current electrical installation) and an electrician.
This saves me not only higher electricity costs but especially the crazy connection fees from Bayernwerke (which were briefly discussed here too). Also the rental cost for two to three cable bridges because the nearest distribution box would have been so far away.