Can't receive SMS (can send, send/receive iMessage)

Hey folks - so I haven't been able to receive SMS messages for approximately 3 days. Here's what I know: 

1. I spent 2 hours on the phone with T-Mobile customer support doing all the settings checks, resetting the network, changing the tower, etc on my iPhone 13 Pro Max. She escalated to engineering support and said someone would get back to me in 72 hours.
2. She mentioned going to a T-Mobile store so I did that. They also checked all the settings and did the network stuff. Didn't resolve.
3. They changed the eSim. Didn’t resolve.
4. I got desperate and upgraded to the iPhone 15 Pro Max. They said they weren’t sure if it was the phone or the service but thought it was probably the phone. Reader: it was not the phone. So now, I have a brand new phone that also doesn't receive SMS messages.
5. T-Mobile store associates told me to call Apple. Called Apple. Support escalated me pretty quickly to a "senior advisor." The senior advisor did diagnostics and phone checks (again, the phone is now 3 hours old). Nothing came back. 
6. He conferenced in T-Mobile. New customer service rep. Tried to get me to do all the same settings checks/network resets as the last one. Said I'd wait for the call between now and 72 hours.

I've read every help thread I can find. It's not anything related to DNS settings. 

Has anyone else had this problem and found any type of solution? I've been a T-Mobile customer for 20 years and have never had a problem like this. The first customer service person kept saying, "Oh wow. This is really rare." The store associates said they'd never seen it before.

I CANNOT DO MY JOB.