Do you think the yellowish leaves are because of n...

We can already say it isn't her fall colours ( senescence ) because the yellowing would not come with burn tips/leaves ( check out my blue dream diary , I have scenescance without the burnt ) and a scenescance would have been different , the yellowing would have been on the older leaves first which is not your case. The same for the nutrient deficiency , it would have been from yellowing from the bottom to the top for a mobile nutrient def ( in your case it can looks like a potassium deficiency but it isn't ) or on the new leaves for a immobile nutrient deficiency ( iron, zinc , ect) . So the only solutions that remain are the Nutient burnt and it looks like that in your case , with burnt tips on a perfectly healthy plant OR the light too close from the plant causing this ( 10 cm is low ) so if I were you I would up that led a bit and low a bit my nutrient input :blush: