Hello, Cradigan1. Thank you for posting your question to the Apple Support Communities. We understand your situation and how you may not be receiving verification codes to your device. We’re happy to help you with the available options here as we understand that it must be important for you to set up and verify your financial apps.
From what we gather, you have not noticed any similar issues when sending or receiving messages to other contacts using your iPhone. If this only seems to happen when you attempt to verify a certain app, we can suggest that you contact the app developer directly for support. The following Apple Support article explains how you can find the contact information for an app developer:
How to contact an app developer - Apple Support
If you ever notice any similar issues with your Apple ID verification codes, we would suggest using the steps in this last article:
If you didn't receive your verification or reset email - Apple Support
We hope this information helps you with completing the verification for this app. Please reply back here if you have any additional questions about how to proceed.
Cheers!