iPhone 14 Pro Max microphone stops working during calls

When I am talking on my iPhone 14 Pro Max, frequently the call goes well for about 10 minutes, then suddenly the person on the other end can't hear my voice at all. They often keep talking for a while, I guess believing that I don't have anything to say, then realize that they aren't hearing me say anything. They try to get me to respond for a few seconds, then hang up. When this happens, I can hear them clearly until one of us disconnects. Occasionally, the last phrase I say gets repeated until they hang up, but I can't hear that. Usually a call back will work for a bit less time than the last call worked, but sometimes that doesn't work either. On very rare occasions, after 5 or 6 minutes of not being heard on the other end, the phone begins to pick up my voice again, and the call can continue.

I've tried all of the "things to do" if the mic isn't working, several times over. Do I need to have a repair or start looking for a new phone? Or is there some additional trick I haven't tried yet that will bring my phone back again? Thanks!