Discoloration, pale and yellowing leaves. Deficiency or fade?

18/6 would be better for your plants, 3 hours of sleep is not enough. They are hungry for potassium.......add a P/K booster to your line up.

It is a deficiency of potassium. Your buds are still growing. Check your ph again. It has likely climbed above 6.2.

I think you need to get your humidity down. 80% relative humidity is a bit hight while in flower. Here's a troubleshoot from Seedsman that deals with at least one problem you're having: black spots on leaves. https://www.seedsman.com/blog/black-spots-on-cannabis-leaves-causes-and-treatments/