iPhone 12 mini not ringing, only vibrates, until I reboot the phone.

My iPhone 12 mini does not ring, it only vibrates; until I reboot the phone. I’ve checked all of the options and did all of the research. To fix this problem, all I do is reboot the phone, and then it works fine – for a while. This happens often. Sometimes it will go a week or more without a problem, sometimes a day or two. All I do is reboot the phone, nothing else, and it’s back to normal. Has anyone else experienced this? Does anyone have a clue as to the issue?