I want to delete device from Domoticz, but its recreated automatically

This is by design, as descriptors are stored on the MQTT broker as retained.

You can delete unwanted device descriptors with MQTT Explorer, they are located under homeassistant/ as default. You can find the devices by the deviceID and type. After you delete the descriptor from the MQTT broker, the device can be also deleted from Domoticz and it wont reapper.