My phone doesn't make a sound for text messages, just for some senders

When my best friend texts me, or I get a text on a thread with my brothers and sisters, my phone doesn't make a sound, even though my iMac does. With other people, I get the expected sound. Since I'm not always near my Mac, this is a problem.

It happens even when I don't have a focus set. Here's what I've tried:

1. My ringer is on. I get my ring tone when a phone call comes in, and I get my message beep when other people text me. I hear the tone on both my iMac and my iPhone.
2. Settings -> Notifications -> Messages has Allow Messages turned on. Allow Notifications is turned on for Unknown Senders and Emergency Contact Alerts.
3. No Focus is set.
4. When I touch my friend's face in Messages, it opens up her contact page. Hide Alerts is off for her.
5. I recently restarted my iPhone (And upgraded to iOS 17.2.1), but the problem is still there.
6. "Filter Unknown Senders" is off.
7. My Bluetooth ear buds are off.
8. My ringtone and text tone for my friend are both set to Default.
9. In Settings -> Face ID & Passcode -> "Allow Access When Locked" section, Notifications is on.
10. Settings -> Notifications -> Messages -> "Alerts" section, Banner Style is Persistent, Sounds has my sound, and Badges is on.
11. I have not blocked any of the contacts in question. I still get texts and phone calls from them.
12. 
    

Does anyone have any suggestions?