Did you ever find a workable solution for this problem? I'm in a situation where I have a custom framework that has a static library as a dependency. At launch I was seeing a huge list of warnings about "Class <...> is implemented in both...", apparently indicating that both the app and the framework were including the dependency (despite the fact that the app doesn't import that dependency anywhere...). The static library (AudioKit) is being included in my custom framework using Cocoapods.
To get around the warnings I tried switching my mach-O target from "Dynamic Library" to "Static Library", based on a note I read somewhere about not adding static libraries as dependencies in dynamic frameworks. Sure enough, this removes the warnings, but then it fails when trying to load resources from inside the framework's bundle using "Bundle(for: <myFrameworkClass>.self)", as you've indicated in your question. (Note that I responded to the warnings not simply because they looked serious(!) but rather because my framework wasn't working properly.)
The answers here, unfortunately, are non-answers... While I understand what they're trying to say, there's clearly some broad misunderstanding going on far beyond this thread, as the framework I'm using, AudioKit, is referred to as "static" in many places online—including AudioKit's home page. Also, when I compile my custom framework with "Static Library" indicated, I very definitely get a bundle in the product package, complete with all the resource files I'm trying to access at launch (i.e., the ones that aren't found because the bundle path is now the app's, not the framework's). Clearly this is super frustrating. The only thing I can think of doing now is grabbing the main bundle's path, and appending the path to my framework. Feels hackish, but I feel like I'm painted into a corner here, so really not sure what else to do...