Monolithic Xcode Workspace
The challenge here is rooted in Xcode’s inability to maintain more than one open reference to a project at a time. If you have a common library “CoreFunctions.framework” and several apps with “CoreFunctions.xcodeproj” embedded in them, then the first app you open in Xcode that references it “wins,” and all the subsequent apps end up with un-expandable proxy icons for the project reference.
The monolithic workspace is a bit unwieldy but great to not have to do the close and reopen dance every time I want to check whether a change to a common framework has an impact on another app.