rudi48 made some investigations regarding power saving during deep sleep here.

Summary:

To achieve maximum power saving during deep sleep it is necessary to switch off Bluetooth and WiFi before calling esp_deep_sleep_start();

Example:

#include <esp_wifi.h>
#include <esp_bt.h>
...
  esp_wifi_stop();
  esp_bt_controller_disable();
  esp_deep_sleep_start();