Had a droopy plant once so i had a closer look and found the stem was missing... apparently something ate the fleshy part of the stem and not the inner stem core.
There's a cloth hanger around the stem with rooting gel in a paper towel covered all up, that's all i know..
This is why is best to get a bag of Fox Farm Ocean Forrest to use with tap water, no need to pH or add anything, just water once a week and enjoying the harvest 😀
Is the soil DIY? It looks like it needs more perlite and less mulch. And yes the 25 grams of ferts burn the roots and the plant is dead.
Don't worry It happens to everyone, you have to fill the experience bin with dead plants first.