@Joseph-Francis-Lambert-Caubo What kind of error are you getting with the 2nd radio? That sounds odd.

Make sure that the Forbid IGMP proxy service did not revert back to being unchecked after the update.

My phone still seems to be working fine. However, I must note that I recently replaced my iPhone XS with an iPhone 12 Pro less than 2 weeks ago, so that may be playing a part as well. The iPhone 12 Pro connects via WiFi6 while the XS only connects as WiFi5. I still need to do further testing on my wife's phone (an older iPhone X) to see if she is experiencing any WiFi calling issues.

I only just updated to 3.4.3 late last night, so I have not been on the newest version long enough to provide any consensus with it.

On a side note, I do find it very annoying that any time I have to reboot my router, it screws up communication with my Hue Bridge (connected via ethernet) and LiFX bulbs (WiFi only). The majority of my lights in my house are Hue. I have to end up power cycling the bridge and LiFX WiFi components after the router reboots to get them communicating properly again, which is annoying since they are not in easy to access locations (I typically end up flipping the breaker to the room to power cycle them). I never had that issue with my previous router, they would recover with no issues if the router lost power or got rebooted. Thankfully, I reboot or lost power situations are rare.

WiFi Calling On iPhone's

AmpliFi WiFi iOS App Feature Requests (as of 1.7.0)