Where's history? You gotta have history. Also something like world cultures, social studies. Why? Because as a race, we just don't coexist well. With anything! We need to be exposed to new things daily. And science. Science!!!!

History, both because a knowledge of what has happened before helps one to understand the present and because of the wealth of transferrable skills it entails and which help to make sense of the strange times we inhabit. (But I would say that, being a historian who often wonders of the three years of poverty I went through in order to get my degree were, looking at my bank balance twenty years later, really worth it).

Some sort of qualification in post-apocalypse practical survival skills might prove advantageous in the near future, too.

Plato's Dialectics and Republic, Socrates, Democritus, Pythagoras et al. can give you much direction to what your asking. It may take some reading, but you will find what your asking

I would say philosophy because the study teaches how to think for ones self in states of being.

History, because without knowing the past one will not understand the present. If one does not understand the present, one will not see the future.

Linguistics to better understand consciousness and the meaning of terms.

How about Ethics??

The answer will depend on your personal goal. Once that has been set then you can choose whatever option will take you there, not the other way around. Example, "a hypothetical student that master books of medicine and memorize tons of technical names, he seems like a big success until he realize he doesn't like to be trapped in a hospital for long hours"........ You must determine first where you want to be and then you choose the means and path to get there

Always start with anything that requires strong math skill. It's the best, deepest way to drive understanding we humans have. Math generalizes well.

Maths, Science, Physics...and Astro-Physics.

Also, health and nutrition.

Science, Technology, Engineering, Medicine.