What’s next ?

I think these things are past saving, my friend. Sorry. My advice is to get new cuttings (this time with roots) or get some seeds and start from scratch. You've given them nutrients, but do not need to give them anything - cuttings just need rooting hormone at the point you put them into the rockwool, then allow them root for a couple of weeks before given them any food. Keep them under a plastic lid (e.g. coke bottle) to keep the humidity really high, chop off all the leaves except the top sets, and cut the tips of any remaining leaves to reduce transpiration (which would otherwise dry out the cutting). I even think it's better to keep them in the dark than full light, so long as your temperatures are in the right range.