Phone rings for split second then ends

When someone calls me, it shows up for a split second then ends. I can call them back and my phone works. This happens whether screen is locked or unlocked. When they call, it is acting like my phone is off in that it isn't going to my voicemail, but I will see it flash then it shows up as a missed call. I have checked to make sure my account is in good standing with my carrier and that others in my house with the same carrier and phone aren't having the same issue. I can otherwise use my phone without issue.

I have iPhone 12 with the latest version of iOS.

I have reset network settings.

I have hard reset my phone.

Call forwarding and do not disturb are off.

I have tried turning 5g and data off.

There doesn't appear to be any carrier setting updates available.