Why does it look like this

Of course, there are friends who are much more knowledgeable than me, but from what I've seen, your light distance from the plant is too far, and since you haven't done LST, the lower branches aren't getting enough light. I can see that there are definitely issues with the pH levels related to watering, and your plant isn't getting the proper nutrition.

What light are you using please

There are a couple of things that might be going wrong here... one of them would be your watering - droopy leaves come from either watering too much or not watering enough (most people will usually err on the side of watering too much!) but there's no information in your diary telling us how much they're getting... are you leaving the pot to dry completely before giving it another dose? If you're like most folks, you're probably reading the crispy leaves as needing more water whereas it certainly might be lockout from a PH imbalance... Have you checked the PH of your runoff?? ... this needs to be between 6.0 and 6.5 for soil ... out of that range, your plant will not be able to uptake a lot of different nutrients and micronutrients that it needs. I also don't see any nutes save for the banana tea which is great for adding more potassium but doesn't address all the other needs your plant has which could be contributing to the small leaves you're getting. Good luck with your grow - I know you'll figure out what's going on and will have a good harvest!

Are you watering it enough? Lack of water would explain the droopy leaves. You still have 4-6 weeks of flowering to go, no matter what the trichomes look like right now, harvest when there are 98-99% brown pistils. Some strains will have nearly 80% amber trichomes from about the fourth week of flowering onwards, and some strains never develop amber trichomes at all. It all comes down to genetics.

Light , FL is out of date, I saw only few in 3 years who grow well under them. And are you sure you have 600W in flower, by plant structure - more like 60.