Pace 5268 and IPhone wifi calling - so many issues
I have a fairly new fiber install running with the 5268 in DMZ+ mode with a Unifi USG pro and 2 UAP AC Pros. Everything works ok except for iPhone VOIP calls. I've spent an extraordinary amount of time on forums reading folks with the same issue. Most everyone either dumps the Pace modem for another or finds a way around it.
Issue - when I receive a call on my ATT iPhone XR the calls keeps failing after 20-30 seconds. Turning wifi off it works fine but i only have coverage by a windo. If i make a call out while on wifi, it works fine for ~15 seconds, then I cannot hear the person on the other line, but they can hear me or vice versa, i call someone and they hear me for 15 secs and then nothing, i can only hear them.
I wasn't really sure where to start, googling around other people say they had issues with the Pace. I saw somewhere else that i should ask for a new modem but it worked fine before i started with the USG. If anything i'd just dump it and go back to the PACE which is garbage but everything worked.
I called support today to inquire about a new modem to try. They told me my bill would go up an additional $7 per month if i were to replace the modem. Doesn't a whole lot of sense and i'm not about to fork over more money.