Probably the most important insight that you can get from Sonnenwende is that Germany can achieve energy independence with 100% renewables in about 10 years from now using an initial capital investment of 8 billion EUR.
And if it can be done in Germany, it can be done almost everywhere. There are only 8 countries in the world that don't have significant land areas below the latitude where Sonnenwende is taking place.
Try it yourself: https://sonnenwende.codeberg.page/
More details and development information: https://codeberg.org/sonnenwende/sonnenwende/