Plant died and then came back to life

Woke up and checked my plant and all the leaves had fallen out of nowhere checked on it before bed and it was looking fine...in a panic I figured change the res water probably had toxic ph level and clean the air stones and lines and see what happens and now the leaves are making a come back but it’s still looking pretty sickly any suggestions on dos and donts right now? I’m figuring I probably shouldn’t add any nutrients at all right now would it help to keep my light on 24/7 instead of 18/6...it’s my first attempt growing and I’ve been making tons of mistakes starting with planting the seed upside down over watering my Rockwool cube with a heavy drip line 24/7 and nute burns somehow the little guy keeps pulling through my errors wondering if all these setbacks may be why his stems are thin and not supporting him well and his stunted growth since he’s well over a month old...some pics from when he was semi healthy and a pic showing the water line to the net pot that I’ve since removed

You have a fan blowing on it? Should thicken up stems

Dead is final. Always. So it never died.

I cant see any roots coming out the net pot? What is that line doing going straight into the net pot? Assume its feeding solution through it, if so I would remove it and start top feeding until roots start coming out the pot, until roots are in the res they wont start taking off.