As you have identified, the Wyze Floodlight requires constant power to operate. Adding a battery backup would have greatly increased the price point for the device I am sure.
Since the Floodlights on the original V1 version are actually an accessory to the V3 Cam that is mounted on it, I doubt you are going to find a direct way for Google Home, Google Assistant, or Alexa to directly action the lights on the Floodlight.
I have been testing my Floodlight Pro with Google Home and have not been successful in finding any way for Google Home or Assistant to action the Floodlights. The only Action in Routines available is Brightness. Alexa, on the other hand, does have the ability to directly control the floodlights. But, the Floodlight Pro is a stand alone Cam, not an accessory to another cam.
While a Wyze Switch may be one solution to be able to control the floodlights, if you want to have full integration (Google Home, Google Assistant, Alexa) you can accomplish that by using a Wyze intermediary bridge. I use a Wyze Plug. The plug is able to be turned on and off manually or by Google Home, Google Assistant, and Alexa or any 3rd party brand compatible Smart Button thru Routines and Automations. Wyze Rules then turn on\off the floodlights when the plug is turned on\off. I currently have 8 Wyze Plugs dedicated as Automation Relays.