I think that this is an interesting question in the sense that there are three possible options, two of which you mentioned in your post.
As far as I am aware, a combination of a Finance and Economics majors is fairly traditional since they complement each other quite nicely in terms of the knowledge and skills that studying them would provide you, and would therefore be a good option to choose if you are certain that you intend to pursue a career in investment banking.
Business analytics is a growing field, and this is a good indicator in terms of finding employment in this field (also using the example of becoming a business analyst). Here, you should consider your career aspirations. Specialising in Finance and Economics would allow you to customise your knowledge and skills in a way that suits a career in investment banking more closely, whereas specialising in Finance and Business Analytics means that you will not graduate with the same depth of knowledge relevant to investment banking, although it would also enable you to seek opportunities in an additional field, being business analytics, rather than potentially one field in the case of the Finance and Economics combination. It is therefore important to consider the career that you would be more interested in and the one that you would have a higher chance of starting.
Alternatively, if you feel that investment banking is for you, have you considered choosing a Banking major alongside a Finance major? From what I have observed, this major emphasises investment banking, which, alongside a Finance major, would not only allow you to gain finance-related knowledge and skills that would be needed for a career in investment banking, but also gain a good understanding of investment banking as a whole.
I hope this helps!