When you switch to flower with photoperiods, it’s usually best to run your LEDs on the Bloom setting or full spectrum with an emphasis on red light.
The extra red wavelengths really support bud development. That said, plants also still need some blue and white light to stay healthy, so I personally recommend running full spectrum during the whole grow and only adjusting intensity or spectrum if your light allows fine tuning.
For autos, the same principle applies they also benefit from more red during flower, but full spectrum will usually give you the most balanced growth and yield. I’d avoid using only red light, as it can make plants stretch too much and reduce overall bud quality.