Hey @BretBays,
Thank you for reaching out to us. You might want to have a look at the Python Libraries Manual. Since Cinema 4D 2024.0 there is also mxutils.LocalImportPath which automates injecting module paths and reloading such imported modules (I probably should update the Python libraries manual).
The "flaw" of all these approaches is that while you still encrypt your plugins pyp file, the imported module(s) py file(s) will not and cannot be encrypted. You can either ship your common functions unencrypted or develop your plugin as a multi module solution (so that you do not have to replicate your code across plugins) and then package up the plugin into a singular file. There are some Python tools like pysconcat and pymerger which can help you with that. But you should be aware that these can fail when you have complex dependencies. You could also serve the py-cache of your modules, but that will not really stop anyone who wants to read your code.
Cheers,
Ferdinand