Adding swift packages to custom capacitor plugins

[jonathankehler]

I have a custom plugin that works fine. I want to add a swift package as a dependency to the plugin.
I want to import this package in my plugin swift code and use it.

Can anyone give me some pointers on how to get started on this?

Feels like i've tried a hundred variations. If I add the dependency in the plugin project then when I do npx cap sync it doesn't seem like the dependency is synced to the main xcode project and opening that shows its not there.
If I add the dependency in the main xcode project after npx cap sync then its importable from all swift files EXCEPT the swift files in the Plugin directories.
No matter what I do, when I open the main xcode project and try to build it the import fails because it can't find the module.

Is there a specific way the dependency has to be added to the plugin project?
Does the dependency get sync'd to the main project and if so how?