@Bryan.L Good day,
Thank you for your detailed post, for the KP303 unstable issue, you could try some suggestion here:
1. Please confirm kasa device firmware and kasa APP version are up-to-date
2. Ensure smart device is connected to main router directly not through AP or extenders
Locate device very close to main router and see if it becomes offline
3. You could try to change a different 2.4Ghz Wi-Fi channel on router and see if that helps
4. Turn off Advanced wireless settings like Wi-Fi Optimizing (Channel Optimizing)/ Band steering( Smart Connect )/ Mesh feature etc.
Can you help confirm some information to locate the issue:
1. The Router model:
Your network topology ,e.g. Router Archer C7 (in living room) <wireless> kasa model XX ( in living room)
2. MAC address of the kasa device (please share via private message)
3. Can you access the kasa device locally (when phone connected to home wifi)when the issue happens? What is the Error you got when bulb disconnects?
4. Signal strength of the smart device: Kasa APP, go to device settings->signal strength ( tap on the Wi-Fi icon/SSID to see the value of the RSSI)
Thank you.