A microcontroller can interfere with the WL-134 module (details in docs below). It seems the documentation comments are directed at 5V microcontrollers. Any suggestions for powering an ESP32 with 3.3V when it is used with the module and a 2S 18650 Li-ion battery (6-8.4V, Nominal 7.2V)?
The rough schematic below is easier to read if you expand it:
