the curling downwards can be nitogen toxicity but it can also be caused by heat stress or overewatering. u need to fix that. when growing in soil the golden rule is 👉 "if not dry, don't apply" (water that is)
the yellowing of leaves ... if it's only happening to older leaves I wouldn't worry about it too much. that's kinda normal and by looking at your other leaves u have plenty of nitrogen
good luck my Iberian comrade!