Hi,
Thank you very much for explaining your use case. At present, SMS OTP for MFA will require our Enterprise plan. I can understand that the pricing model may not seem to fit what you were hoping for but there are many added benefits for most customers that require the type of technical features you are looking for and the value overall exceeds the cost. Unfortunately, we don’t support customization to our self-service plans (such as the Developer Pro plan) to incorporate individual features offered in our Enterprise plans. I will, however, provide the feedback you’ve given us to our sales and pricing teams for consideration.