Would dosing N and P have a significant impact on plant growth? Sorry, I'm new to fertilizer dosing.
Yes; plants require macronutrients and micronutrients. We need to provide three macronutrients (nitrogen, phosphorus and potassium) to plants in order for them to grow.
Without these nutrients, plants will not do well.
For more information regarding fertilization and plant well being, please take a look at my guide to planted aquariums, linked in my signature below.