@hjenkins 

Were you able to reconnect this P100 to Tapo APP and Google Home APP successfully? Was there any error message when reconnecting to Google Home? Kindly share a picture of the error if there was one. 

Please confirm whether other Tapo devices can be controlled with Google Home normally.

Check whether you can control this Tapo P100 remotely with Tapo APP while using cellular data or other WiFi? 

Have there been any recent updates to your Tapo app, device, or the Google Home app?

  @hjenkins 

It's a pity that the problem did not resolve. The problem with your device is actually a remote control issue.

Google Home relies on remote management support from the Tapo device. If the Tapo device can only be controlled within the local network (i.e., the same Wi-Fi network as the smart device), it will appear offline when you switch to mobile data or connect to another Wi-Fi network. Third-party service doesn't work as well.