Text messages (not iMessages) not sync'ing between iPhones

I have an iPhone Xr (personal) and iPhone 12 Pro Max (business). For years everything had been perfect...then the most recent update to iOS 16.3 happened. This put both of my phones in this "time limit" scenario even though neither Screen Time nor time limits had ever been turned on either of my phones. After hours with AppleCare, the final result was a hard reset of both phones.

Now that I have both phones hard reset, I am not getting text messages (not iMessages) to send across both phones. That is, if I receive one to my personal number it won't show up on my business phone, and vice versa. This always worked successfully in the past.

I have done the "Settings->my name->iCloud->Show All->Messages->Sync this phone" thing. I have also done the "Settings->Messages->Send&Receive->sign in to account" thing where it allows imessages (noting that it does call out only imessages here) to be received from both numbers on either phone. I have done both of these to both phones.

The problem still exists that text messages are not showing up on both phones. How can this be fixed and put back the way it was?