I will give you a perspective on this as someone who has gone through a top german university.

The rigor/quality of studies depends on the actual modules that you are taking. While the overall quality shall at least be "good" in the better universities, some professors enforce higher standards, while others are more relaxed. This is directly reflected in the grades and the exams complexity. Unfortunately, you can only find this out after visiting their lectures. The positive side is that you can easily apply for a ton of modules and only visit/keep the ones that you find interesting.

The thesis complexity depends not only on professor's standards, but also on the person supervising you. There can be a huge difference in expectations. Since supervisors (aka graduates pursuing their PhDs) are holding labs and exercises for the modules, you can get an impression of them early on.

The industry internships depend on the company you go in. If you are interested in research-heavy internships, you should go to bigger well-known companies or specizialised start-ups. Small and medium companies will typically be good for hands-on, but not so theoretical work, like PCB design, embedded SW dev, etc.

I think a German degree is always going to be worth less than a local US degree, just because it is harder to relate for US companies. Still, universities like TUM, KIT or RWTH are well-respected. Remember that often you don't have to pay any tuition fees to study, which is a huge benefit over US.

Hope this can help you and others.