You can mix them, it just has to be released as a binary framework which is a bit annoying as I would prefer a pure source release but it does work.
My involvement with MacOS development is somewhat limited and I have no plans publishing any packages yet ;)
For whoever comes after me... When ChatGPT suggests changing your Objective-C from this:
#import package.h
To this: #import <package/package.h>
Just skip that rabbithole of inifiny-nested failure, and just do this instead: @import package;
And you're done. You can thank me later :)