It’s fine to be interested in both. You can major in economics and still fulfill the pre-med requirements. 40% of all medical school students majored in something other than STEM subjects. The tricky part is the works experience/ECs that you need. Medical schools want to see medical volunteerism, research, shadowing. Investment banks and consulting firms want to see work experience. You can go down either leg of the trousers of time (to quote Terry Pratchett here), but be prepared to spend a year after you graduate shoring up any weaknesses. For example, if you don’t do the medical volunteering and research because you were working, you’ll need to do it before you apply to med school - they will want proof that you’re committed and know what you are getting into. On the IB side, they have so many applicants that they can afford to be picky and chose people who have demonstrated a long term interest in the industry. Consulting is a bit less rigid since they need people with a wider variety of background (but want very strong analytical and communication skills!)
And as others have said, take classes that interest you. It’s not ‘padding’ your GPA to take something other than a hard core required course. A little breadth, a bit of personality reflected in a transcript isn’t a bad thing. Ditto when it comes to ECs. You never know when your interviewer will turn out to share your passion for music, theater or whatever. (I’m taking my cues from you, by the way, and speaking only of ‘whats in it for you’ in pursuing your ECs rather than all the reasons a human being might want to be more than a drone zeroing in on the best paid most secure job they can.)
By the way, there are many careers in medicine that don’t involve patient care and are therefore not about ‘caring and compassion.’ Medical research is just one example.