Hi heliwolf65,
For help with ensuring alerts are delivered at full volume while looking at your screens, check your Attention Aware settings with the information below found in the article here: Turn Attention Aware features on or off on your iPhone or iPad Pro
"What are Attention Aware features?
Even if you don’t enroll in Face ID, the TrueDepth camera* intelligently activates to support Attention Aware features. With Attention Aware features, iPhone can check whether you’re paying attention to your device and automatically take action. For example,
- When you’re looking at your device, your display will not dim until you stop looking at your device.
- If you're looking at your device, it will lower the volume sound of your alerts.
If you don’t want to use these features, open the Settings app, tap Face ID & Passcode, then turn off Attention Aware Features."
You can also check your notification settings to add a banner to ensure you see the alert if you miss the sound. The guide here will assist: Change notification settings on iPhone
Cheers.