You should lump all interests together in one ad set because people can be interested in multiple things which will reduce your overlap. Similarly, if you’re not messaging each interest differently, there isn’t a point to separate them. In general, you want to pick an objective that is aligned with your business goal (i.e. if you want sales you need to track with your sales with the fb pixel) and then setup a fairly broad audience (e.g. multiple interests, maybe more than you think is relevant or use lookalike audiences based on desired behaviors like sales) finally letting the algorithms go to work.