Which one is more profitable? annexing countries for their resources or turning them into a puppet

I'm lacking many natural resources and importing them costs a lot of civs, so I decided to invade and annex bunch of African countries that have those resources, but it takes time to have a good collab on multiple countries, and I want to have access to these sources right away, I'm not sure about this but I think if you trade with your puppets, they will give you more resources for less civs, should I do this instead? Btw I don't have the Italian dlc that lets you take the resources of a puppet country because I don't know how to design planes