First, I wouldn’t advise extending your time (and cost) as an undergrad to add a 2nd major. Second, if you add a 2nd major or minor, I think that it being a practical help with employment (but of course your interests as well) is the way to go. For example, my son is majoring in Business/Finance and adding a minor in Math.
Adding minors or 2nd majors in Comp Sci, Math, Stats, even a second language can be helpful for your career.