No incoming text notifications and text sound is very faint.

This question was previously asked but I don't see a logical answer. My home screen on my Iphone 16e quit displaying notifications. I do not know I have any unread texts unless I have to open my notification page each time. The sound is very faint also. The phone is not on silent. I have to turn the volume up completely high to hear it at all. Before this began, I could hear it from room to room. I have taken it to 4 different places, and called Apple twice. I still have no answer.