That under growth you want will NOT flourish now that yo have cut their power supply.

Each fan leaf is dedicated to the secondary growth. The fans are there for a reason.

In flower, if you cut the fans, you will cease the flower growth.
In veg, if you cut the fans, you will cease the secondary growth.

It is a weed. Leave it alone.

Oh...lose the 2700K lights during this stage. Useless. Replace with more 5500K + bulbs.