Intermittent message notifications on iphone 12

For the past month my phone has only intermittently(mostly not) given me audio notifications on incoming messages. I have 3 devices-iphone 12, latest iPad and apple watch 8, and all have the latest iOS installed. I RECEIVE every message that people send me on every device. The problem is my phone hardly ever makes an audible notification sound anymore, so unless I hear the iPad make noise (sometimes it does but not always) or feel the haptic buzz from the watch on my wrist, I miss most of my messages. I have gone through all the usual suggestions-do not disturb, notification settings, simple volume check, immediate delivery of messages vs scheduled summary, notification grouping, phone set to"send and receive from my phone number" etc etc, all to no avail. I've checked all my contacts and no one is set to "hide alerts". It doesn't seem to matter if it's a group text, individual text, Android or imessage. It will be intermittent within the same thread of a chat, and again group or individual doesn't seem to matter. It also doesn't seem to be person specific, for example, my husband will text me and the phone plays his notification sound, he sends me a text again 2 minutes later and no noise... But the text will come through both times. I literally need to be sitting there staring at my phone screen all day if I don't want to miss a message. Any suggestions?