1) Mindset and Culture. The idea of entrepreneurship, hard work and reward for risk is becoming completely alien to Germans. New technologies and high growth sectors are almost exclusively perceived in terms of their risks and downsides. Security, reliance on the government for problem solving and tall poppy syndrome are paramount.
2) Overly complex civic systems. Germans always were famous for their bureaucracy. But government interference in the most minute details of running a business, endless red tape and micro regulations have made it largely impossible to be competitive on the international stage.
3) Poor Work Ethic. What? The Germans? Aren’t they known to be the hard working ones? Well - somehow, our trains are also known to be the punctual ones. These cliches might have been true during the “Wirtschaftswunder” - but today, Germans work the fewest hours of any OECD country.
4) Climate Focus. Germany’s government is focused on a largely ideologically driven understanding of climate change prevention. It’s not just that Russian gas is no longer available - in addition all nuclear power plants were shut off. Climate regulation and taxation also adds to rising energy prices and production costs.
5) Worker Rights: Germany has very high levels of worker protections, making it hard to scale workforces up and down and near impossible to dismiss employees for performance reasons.
6) High Taxes. Germany has some of the highest corporation and personal income taxes in the developed world. And while e.g. Scandinavian countries have even higher taxes, in Germany it doesn’t feel like you’re getting something of equal value back from the state. This is of course highly subjective.
7) Few Future Industries. Germany’s industry has focused on gas powered mobility and advanced machine building - and has become a world leader in many of these areas. It has, however, very few software, AI, or other companies that make up the bulk of e.g. the US economic growth.
There’s probably many more - but this might paint a picture from the inside.
The points you are making sound a lot more like what you would find as political campaigning talking points for deregulation than what's actually transpiring with the German economy.
To 1): Entrepreneurship has always been a lot lower in Germany as in many other countries, as it's not seen as e.g. a capitalist virtue as in the US. The German economic model with it's widespread Mittelstand works well with few entrepeneurs and a large portion of the population working in those enterprises. Not everyone has to be a small entrepeneur and hustle all the time.
To 2): Again, basically the same as it has always been. For the typical company there isn't any more "government interference in the most minute details of running a business" than 20-30 years ago. One also has to keep in mind that (as in most countries) that as long as you are making money and act in good faith according to the spirit of the law, the regulatory bodies are a lot more bendy than one might assume according to the letter of the law.
To 5): You can very much scale your workforce up and down. Limited time contracts and long trial periods are very common. On a larger scale that is typically done via subcontractor structures. Also the typical reasons for wanting to scale down (economic non-viability) are permissible reasons for letting people go. It's also very much possible to fire people for under-performance (you just have to go through the motions of tracking their performance and comparing it to peers or documenting their non-compliance). The only stories I'm actually still hearing in the wild of people not being able to be fired is about "Beamte" (public servants).