Hello, friend! 👋
The reason for your problems is the incorrect pH of the hydroponic substrate!
If there is no soil in the substrate, then it is considered hydroponics!
In hydroponics, during the middle of flowering, I recommend keeping the substrate and watering pH at 5.8. Your 6.6 pH is not suitable for successful cannabis cultivation! Adjust the acidity, and the plant will find it easier to flower and develop buds! At the ripening stage, make the pH 5.7! Before harvest, in the last week, do a flush with a pH of 5.6-5.5! 👌
Good luck, bro! ✊😇