That's been one of the biggest lessons I've had recently.
The deal is that it depends on the plants in large part. And as far as I can tell there is scant literature that describes ideal water column nutrient concentrations for each plant type. The businesses that sell the plants certainly don't mention it. I had been running lean (running nitrates down to 0 or close to it and then replenishing for the next day). Many of my plants were doing really well like rotala, ludwigia, etc... they got very red and grew super fast. But Java anything was not doing as well, not dying but not looking great and not growing. Also I was ready to tear out my AR mini it because it was never looking good. I then upped nitrates and all the plants that weren't growing or looking good, suddenly were. My java swords for example that sat and did nothing for nearly two months, started growing. The AR that sat and was getting GSA on it, suddenly got larger and lost all the GSA.
To add to the confusion, there is also a lot conflating on these threads of ideal PPM concentrations with weekly dosage measured as a PPM. Sometimes it's not clear which quantity someone is referring to e.g. "I do 10PPM of nitrates" - not clear if they mean they keep a minimum of 10PPM of nitrates in the water column at all times or if every week they are dosing 10PPM worth of nitrates.
What I learned, unfortunately after stocking my whole tank, is that some plants like high concentrations and others don't. If I were to do it again I would do a lot of research into which plants prefer what concentrations and select plants based on that (e.g. not try to force a plant that prefers lower concentrations into a tank where I am maintaining high concentrations or vice versa).