We just developed, tested and added Tasmota32 Berry script GGreg20_V3 driver for ESP32.

You may find this example code at GitHub following the link: 

https://github.com/iotdevicesdev/ggreg20-v3-tasmota-esp32-driver

News on this is here:

Kyiv, Ukraine. 09/01/2022. The IoT-devices team developed, tested and made available on GitHub a ready-to-use GGreg20_V3 driver for ESP32 with Tasmota firmware and Berry scripting language.

https://iot-devices.com.ua/en/drajver-ggreg20_v3-dlya-esp32-z-proshyvkoyu-tasmota/

The driver allows you to receive pulses from the ionizing radiation detection module GGreg20_V3, accumulate them and calculate the radiation power (uSv / h), radiation dose (uSV) and moving average (MA5) radiation power (uSV / H) within a five-minute buffer.