how could i delete esptool.py v2.6 and install septool.py v2.5?
If you turn on verbose output during compilation (File > Preferences > Show Verbose Output During: > Compilation), compile any sketch, and then examine the contents of the black console window at the bottom of the Arduino IDE window, you will find the path to esptool.
You can find the download URLs for the various esptool versions here:
https://arduino.esp8266.com/stable/package_esp8266com_index.json
or perhaps here:
https://raw.githubusercontent.com/espressif/arduino-esp32/gh-pages/package_esp32_dev_index.json