I guess Nitrate is the form of Nitrogen. Common forms are Calcium Nitrate, Potassium Nitrate.
There are other N forms such as Urea.
Ammonium Nitrate would supply N in two forms, but lower Nitrate % than straight Nitrate forms for the same total N.
There are also newer slow release complexed N forms that need to break down to release. These are large N molecules, often used in pot mix to time release.
Organic forms can be slower release, lower Nitrate.
The label of the fertiliser should detail the Nitrogen forms that give the total N for the 6-4-6 or 20-10-20
It should say % Urea or % Ammonium nitrate
High Potassium fertilisers could be Potassium Nitrate based as fertilisers are made to a formula to get the NPK and micro balanced
This is the easiest way to get high N high K.
Organic forms can be slower release as discussed above.
Nitrate has problems, but so do Urea and Ammonia in high doses to plants.
I have made a few bungles by charging off on a new direction.
My policy is now add less fertiliser apply twice and see what happens.
I have also repotted with high fertiliser, only to get super growth and pots outgrown quickly.
Apart from Brix to plant health there is also this.
High levels of nitrate in vegetables are frequently reported. The potential hazard of vegetable-borne nitrate is from its conversion to methaemoglobin-producing nitrite before and/or after ingestion. Methaemoglobin cannot bind oxygen and produces a leftward shift in oxygen-dissociation curve, causing hyperaemia.
https://www.horizononline.com/nitrogen-in-slow-release-fertilizer/https://pacificfertiliser.com/slow-release-nitrogen/3311/