Hi kelel8961,
If we understand correctly, you want to make sure you're receiving notifications in general, but you only want to hear audible notifications from a few specific contacts, and you already looked into Do Not Disturb and Focus. Is that right?
Your best option might be to put your iPhone in Silent mode with the Ring/Silent switch: How to put your iPhone on vibrate, ring, or silent mode - Apple Support
Then, you can open the Contacts app and tap the contacts in question and then tap Edit. At the top of the Edit screen, you can turn on Emergency Bypass for the people you want to receive calls from.
If that still doesn't do quite what you're looking for, you can always send your suggestion to Apple with this link: Product Feedback - Apple
Take care.