Runtz Muffin – Grow 001: Closet grow

So after bouncing back from the issues with the soil I’ve seemingly run into some other root problems. Concerned it could be fungus gnats as I’ve seen one or two suspicious flies in the grow room, hence why I moved Runty to a sanitised closet. She is very droopy and has lost the rich green she just reacquired. I’ve also got some strange deficiency on the leaves which look like ph problems. Not sure what else it could be but any advice would be great. My inexperience is very much showing in this plant.