Update FYI: there was a firmware update for the Boost devices (v1.32.28) on Nov. 13. This update was released BEFORE the technician arrived but hey it might take time for this info to trickle through the chain. The agent claimed that it should update...
I'll add my name to the chorus here - over 30 devices in the home, all phones and laptops are Apple. See the same issue staying connected to a 5Ghz network. Same as @Jammer005, I've turned off 5Ghz on the modem and left on the 2.4 for older smart dev...