If it is nute burn then you need to flush only give it water for a week or so then start it back on nutes at like a half dose. im thinking you have nute lock and the plant is not growing because it is just trying to live give it some time and it should come around but it will always be behind...
first off atuo flowers dont look different secong you can tell its an auto flower if it flower before you change to 12/12 or if you change and nothing happens. the leafs look like auto flowers wtf
that kind of production from a plant comes from understanding of grow methods traning your plants and figuring out what not to do and what to do i would start with a soil grow from the first time. hydro can be a hard thing to do because your mistakes will not be buffered by the soil