For iOS, no XCode template for creating frameworks exist. Reason seems to be that Apple doesn’t want that people create dynamically linked libraries, so they just removed it completely.
But for sure, using static libraries is ok, there is even an XCode template for this. People said that they published apps to the Apple AppStore that use frameworks with static libraries, and that they did get approved without problems.
So, go and create frameworks that work on multiple architectures using static libraries and bundle resources, and make it easy for 3rd parties to add functionality to their projects