For six years, I worked in the U.S. for a German company. For the past five, I’ve worked in the U.S. for a Chinese-owned business. Thus, I’ve been heavily exposed to both languages in the course of my career. Per the prior comment, it’s true that English is very widely spoken in Germany and Switzerland. However, knowledge of the language can be quite helpful if you plan to live in either place in the future. There is a significant social and professional benefit to being able to speak to people in their native language.
Chinese is spoken by over a billion people, but almost all of them live in China. Learning the language is extremely useful if you envision working in China. However, English is still predominates everywhere else in the world.
I suggest studying the language that interests you more. That can be a function of your future work interest, but also which type of challenge you want. Since English is rooted in German and largely uses the same alphabet, it can be easier to learn. Chinese is a bigger challenge, since it relies on characters and it much more sensitive to the tone of your voice. That can make studying Chinese more difficult initially, but a satisfying accomplishment of you gain proficiency.
Good luck with your studies.