i wouldnt be chasin ph or some mystery bottle fix yet

soil at 6.5 aint your trouble. that plant looks more like the rootball/water balance is off. leaves hangin but the main sticks still standing usually means the plant aint moving water right thru the roots. could be too wet down low, could be the soil got dried too hard and went hydrophobic. new bag dirt will fool ya that way especially that peat heavy commercial stuff

top can look dry while the bottom is a bog
or the top can be dry and water runs down the sides while the heart of the pot stays bone dry

first thing id do is stop changing 5 things at once. autos in flower dont like a bunch of panic moves. them Gelato auto candy plants are touchy little things compared to old heirloom dope that had to survive weather bugs and rough hillsides

pick the pot up. that tells more truth than a meter

if its heavy
dont water. get the pot up off the floor/tray so air can get under it. make sure she aint sitting in runoff. keep a soft breeze in the room but dont blast her direct. cold wet roots will make a plant droop like that for days

if its light
water slow. not a flood. give plain water around the whole pot, wait 10 min, give a little more, wait again. peat/soil can repel water once it gets too dry just like forest duff in august. you gotta let it soak back in. water till the whole rootball takes it even, then leave her be

also check those ties around the main stem and branches. stems swell in flower and a soft tie can still choke a plant if it gets tight. seen plenty of plants act sick when they were just being strangled by training wire or string

i wouldnt feed just because she drooped. she aint starving from 2-3 days no feed. if that new soil is hot already more food can make it worse. let her stand back up first then come back with a light feed if she asks for it

need to know

pot size
soil brand/type
last time watered and how much
is the pot heavy or light right now
temps and rh lights on/off
is that white unit blowin right on her

my guess from the pics is root zone air/water issue more than wind burn or light burn. get the roots right and most times the top follows. real medicine starts in the rootball not in the bottle aisle

What is your lighting? Is it at 80-100%? How high is it above the plant? Whats the humidity and temps in the tent? Just from the photos she has decent color, but seems like the lighting might be off, my 2 cents.

Classic signs of overwatering
I would reply to the others mind as there might be more than one problem however deff overwatering

Ai Chat says
Common reasons a plant can look like this include:

• Watering issues (either too much or too little)
• Root-zone problems
• Environmental stress (temperature, humidity, airflow)
• Nutrient imbalance
• Light-related stress