Have a look here: BME680 Observed gas 'ohms' readings I tested a couple of BME680s and found that you really need to use some wire jerky to get reliable temperature measurements. Even a Pi Zero produces enough heat to throw off the messurements by over 3C.
Things are not quite as bad, but still bad, if you also have gas measurements. Apparently, one of the Bosch libraries does temperature compensation but this hasn’t made its way the into the Python code.
If you use the BME680 with some wires the temperature will be extremely reliable. The humidity feels low, but apart from some non-scientific testing I have no way of calibrating it to see how accurate it is. The air quality reading is still all over the place as users try to make sense of the Ohms readings (I can’t).