Anytime you get into the 5ph range you are in risk of aluminum toxicity, which reduces the plant's ability to absorb water and nutrients, such as phosphorus, magnesium, and calcium.
Sulphur is an immobile element in the plant. Availability decreases below pH 6.0. I'd add some sulphur, often overlooked macronutrient. Looks like it to me.
Good nitrogen sulfur fertilizers include ammonium sulfate, calcium ammonium nitrate, and YaraBela fertilizers.