I’ve measured the camera’s power consumption. It draws about 310mA in ‘Day’ mode, and 430mA when the night-mode IR LEDs are turned on.
Turning the camera ‘off’ has no appreciable impact on power consumption (which is to say that ‘off’ is not really off).
The USB power unit that comes with the Wyze V2 is rated at 1 amp. Wyze chose to provide a 1A unit since (a) it’s a common, inexpensive commodity design and (b) you can daisy chain the power wiring and drive two cameras from a single power unit.
The OP’s 20000 mAh Anker battery pack will power a V2 camera for over 60 hours in Day mode. If the camera is configured to activate the LEDs at night, the run-time will be reduced.