I can’t take 80% of my network down right now, but I did configure the Ubiquity AP to block wifi access for the chime module (it uses channel 11). I then did a complete (15 second) chime reset and specified channel 6, matching the Netgear R6230 router settings six feet away (running as an AP). It refused to connect. I tried again after unblocking it on the Ubiquiti. It connected to the Ubiquiti using channel 11 even though I specified channel 6. My SSID for both APs is hidden. The Netgear now uses 20 MHz channels while the Ubiquiti uses 40 MHz (both were previously 40 MHz). When the chime module is reset, it broadcasts its own SSID on channel 11. I wonder if it just prefers that channel for some strange reason?
My confidence level in the chime’s reliability at RSSIs well above 70 isn’t very good, but it does seem to work. I’m not going to reconfigure my entire network, so I guess I’ll just live with the chance of missing some notifications.