Say I want to donate to a German charity (one that helps the people of Germany, not just a charity based in Germany that helps people elsewhere), but within that scope I want to choose the charity that aligns most with EA principles.
Are there any specific organizations that have been recommended by the community or any resources that I can check for this?
It takes a lot of effort to find and evaluate effective charities. GiveWell and OpenPhilanthropy focus their charity evaluation efforts on charities that work in developing areas where there is greatest need for improvements in health, education, economic growth. You won't find a lot of detailed EA analysis of charities that only work in developed countries like Germany or Australia because it's unlikely that we can have close to the same impact in these well-developed countries with good living standards.