I love them both so much but I think Shakira is more global? idk tbh it's really difficult to compare them because Shakira is not at her commercial peak right now. But if we look at their entire career trajectory I think they are sort of equal?
Rihanna because she's big in every continent Shakira is big in, if not bigger.
Plus Rihanna has the U.S., a country Shakira hasn't been successful in since 2006.