Setting the gyro orientation is mandatory. Without it, the drone “doesn’t know” if it is actually in the flight position commanded by the pilot. It’s obvious that a rotated gyro chip inside the firmware would cause confusion. For example, if the pilot commands a forward flip but the chip registers a sideways flip, something will be wrong. Luckily, Betaflight has safety features built in that will shut down the drone or prevent it from taking off if it detects such implausible movements.
If the movements of your drone in the first tab of the configurator don’t match what you see on the screen, you need to adjust the gyro orientation.
To do this, look at your FC. On the top, there is usually a printed arrow, which should ideally point forward—meaning in the flight direction. If the arrow points in a different direction, choose one of the following options from the dropdown menu on the right under Gyro Orientation: