Diagnosis
Deco's band steering is too aggressive for your environment. It's pushing devices to what it thinks is the best band, causing disruptive switches.
How to Fix It
Turn OFF Smart Connect. In the Deco app, go to the main network screen, tap 'WiFi Networks', then 'Smart Connect'. Disable it. You will now see separate 2.4 GHz and 5 GHz network names. Manually connect video call devices (laptop, phone) to the 5 GHz network only.
If That Didn't Work
Your Deco units may be placed too close together, creating excessive overlap. Try increasing the distance between them by 10-15 feet. This creates a clearer signal boundary for devices to latch onto.
Heads Up
Some older IoT devices (smart plugs, cameras) require the 2.4 GHz band. After splitting the networks, you must connect those devices to the 2.4 GHz SSID. They will not see the 5 GHz network.