Why Isn’t it growing?

is the space just going to be empty? If so, keep it. If you can replace it, sure i guess... But, just be patient. Not all plants are on the same biological schedule. If you are giving it long-nights, it's in flower whether you can see it or not. being slow does not correlate with greater herm risk, so that's not really a concern either. Also, you have weeks of time to recognize and pull a herm before 1 single grain of pollen is released. As long as you don't ignore your plants, you won't have a problem with pollination even if 1 does herm. there is no risk being patient. There's definitely some nutritional issues - the severity of which doesn't raise concern about herm either. You have time to diagnose patiently and try to fix it. Did you amp up p and k recently? Too much of either can cause chlorosis in new growth -- symptoms are not discrete, there are other possibilities. Could be low S. Even a trace element or two might present like that, so you'll have to eliminate possibilities, as not enough info is given in these questions.