Notification sounds

I have been having this issue for a few weeks, mostly since I downloaded the newer iOS 15 versions. I updated again last night to 15.3.1 and am still having the problem.

I am not receiving sounds for my notifications when I am sleeping/when my phone is not in use for extended periods. I often work at night, so this is even happening when I sleep during the day. This includes making sound for contacts I have set under Emergency Bypass. This has been happening whether my phone is on regular silent mode or Do Not Disturb. I have focus features turned off except occasionally turning on DND when I sleep. I am not using Sleep modes or anything like that. I have checked all of the notification settings, ensured sounds are on and persistent. I restarted my iPhone. Today I even left it in sound mode (silent mode turned off) and I still had the same issue. No one notification sound until I unlocked and looked at my phone when I woke up.

When this happens I will look at my phone and see I received an important call or text while I was sleeping. If it is a text then the notification sound will play shortly after I have started looking at my phone and it is unlocked. With text or iMessages sometimes it will play the sound and display the notification banner as I am reading the message it is alerting me about.

I am a nurse practitioner who works with mothers and babies. I am often on call and need to receive calls, texts and notifications immediately no matter how long it has been since the last time I looked at or locked my phone. It is actually dangerous for my patients for there to be this kind of lag in notifications. I need my sounds to work no matter what. Especially on numbers I have set up for Emergency Bypass.