I want to add Dht11 sensor to it but do not have ESP devices.
Can I directly plug the sensor on pi gpio and read data from there or I have an arduino which would take data from Dht11, put that in serial which would be sent to pi via USB.
Then how to integrate that data into homeasssistant ?
If you want / need to go without hacs, you can use python to read data from the pi pins and get them into Home Assistant via mqtt
This also allows for remote dht sensors with other pis / pi zero W..