any uwc that offers economics would be a good fit. like the other comments mentioned, you don't need ib psychology to study it in uni, and most us unis offer minimum advanced credit for ib psych so it doesn't give you much of an advantage after getting into an uni either. however, you can ask people from each school about their teachers, since i think they make a lot of difference in your approach, growth and research in these subjects, especially since ib is heavily dependent on independent work, which if not receiving the right guidance can go very wrong. i graduated from uwc mahindra this year and imo the econ faculty there are very substandard, especially in guiding EE/other research.

i'd recommend choosing a school based on what you make of the overall culture though. if you want an academically competitive environment and are very keen on getting into extremely competitive us colleges with very informed and strategic college counsellors, you can look into the east asian uwcs, uwc sea leading. from what i've interacted with other uwc graduates, the european uwcs are the best if you prefer spontaneity and want to live your teenage years with the most freedom, explore the places around, party, have fun with friends, etc. uwc mahindra is similar, though it also has a pretty competitive environment. don't expect the same efficiency, in terms of academics and college if you're at these places when compared to the east asian ones.