Is There a Constraint in Modularization?

I'm a big fen of modularization. Even though it does add a bit of overhead, it really helps me stay focused on where things should go. If i have something that will have to be shared between the ap on all platforms, makos, et cetera, then i know it has to go into that foundation level framework. That's kind of more important when i'm working on my own compared to what exact like metaphors am i using, right? Like, am i using a protocle here, or struct or are i using a view model, or am i implementing this as a service?