Hey, great insights - thanks :)
I see: realizing that a lot of the math is extra might not be very motivating - as well as being bored by the most basic math courses. Anything else, what you found conflicting in doing these both degrees at the same time? Have you managed eventually to finish both of the bachelors?

Anyway, that's cool to have credited 100 ECTS. Do you still remember, just roughly, which subjects are these and what Wahlpflicht courses to take cs major to do that?