Thanks for reaching out oceanpaddler,
It sounds like you are using dual SIMs and want to know if you can set up a ringtone for your primary line, and a different ringtone for your secondary line. We can help.
This feature is not directly available currently. You can submit Product Feedback if you'd like to share your thoughts about it if you would like.
In the meantime, there is another way to accomplish what you are trying to do to some degree. While this won't work for contacts that you don't have saved, you could definitely manually assign a ringtone for contacts associated with one number, and another for the other.
For example, you could set it up so that your "Work" contacts use the 'Chimes' ringtone and your "Personal" contacts use the 'Cosmic' ringtone so that you know by the tone which number is being called.
There are definitely some limitations with this workaround, unknown numbers will still play a default tone - which you could use as a third ringtone option until you get them added to your contacts. Also, if you have the same contact in both groups, meaning that either number could be called by them, you may also have some issues with this approach to clearly identify which number was called. But, that said, this should get you as close to your goal for the meantime.
You can check out this article to learn more about how to Use tones and ringtones with your iPhone or iPad.
Hope that helps.
Take care.