Thank you @BriceApp !!! And thank you jefftb78 on the original post if you are around here. This appears to have worked! After I took the steps in his post, I have now had a credit card charge and a 2FA text message come in, both handled correctly! YAY!
To continue the tradition, I updated his instructions for today's devices/settings:
1. Under Apps/Messages/Send & Receive on iPhone, unselect your phone number as a place to send and receive iMessages. You should only have your Apple ID/email address selected.
2. Turn off Apps/Messages/iMessage slider for 5 - 10 seconds. Just long enough for us to be sure it registered everywhere.
3. Turn iMessage back on. At this point you should only have your email address as the sender/recipient of iMessages.
4. Wait until you get the pop-up notification that (paraphrased) “your Apple ID is now being used for iMessage on a new iPhone”.
5. After you get the notification that your your Apple ID is now being used for iMessage on a new iPhone, you can change the iMessage settings to allow your phone number to send/receive iMessages again. Just don’t unselect the email address and only leave the phone number.