How to earn a Bachelor or Master without attendance? This might sound like a strange question, but I was wondering, if you can skip the whole studying part at university and jump right in to the finals and the thesis?

I know, that you have to have a certain amount of credits, but can you get them once and "use" them to get multiple bachelors?

Let's say for example, I want to get Bacherlors Degree in Completely unrelated fields like in Engineering, Orchestration, Computer Science, Aviation and Medicine.

Can I (for example), just study Medicine and use the credits I earnd there to also earn the other ones (so I just have to write the thesis)?
Because a lot of courses don't have minimum attendance.

I don't want to discuss whether something like that (getting degrees without studiing at the university) makes sense or not. (Because it doesn't).

The Idea is more like, go and study something for your self and then go to get the degree without having to attend the full number of years, it would take to study.

Do you get what I'm trying to say?
It is already possible to do that to some extent in many US universities, these are called majors and minors, in your case it would be having multiple majors. Yes you can use the same credits for different degrees but there are only a limited amount of overlapping credits in our related fields. Additionally, I think it will be more complicated to have majors across colleges. Bottom line is that you can only "reuse" a limited amount of credits, so you will still have to take many exams to get the additional credits, regardless of whether attendance is required or not, because you also have distance learning that doesn't require attendance.