It turns out, the Edgerouter won't work in this case (FTTN) because of the AT&T provided router.
However, I have found a third-party developer (https://ddnsbroker.com
) who is willing and interested in adding support for Sonic's API into his product for MacOS. All he needs (in his words) is a: ...complimentary developers account for test purposes.
Which makes sense.
I can provide the developer's contact info, plus whatever else you need. If you are interested, let me know the best way to get in direct contact with you.