Nitrates will always climb. Nitrites will go to zero. One bacteria turns ammonia into nitrite. Then a second bacteria will turn nitrites into nitrates. That’s the cycle. Once the tank is fully cycled and stable you will have 0 ammonia, 0 nitrites, and your nitrates will go up over time between water changes. You decrease nitrates with regular water changes. You could add live plants which will use up some of the nitrates, but won’t get them all. Regular water changes are best to keep nitrates low. Only feed as much as your fish will eat in about a minute. Flakes for fast moving fish, they will eat them all. Slower eating fish and fish that exclusively top feed, use pellets that float. They won’t miss food and leave waste at the bottom. Most fish handle nitrites up to 40 pretty well in freshwater, and if it’s a slow climb they can acclimate to very high nitrates, but then it’s a long slow process to gradually bring them back down to normal nitrate levels. Nitrates aren’t as toxic as ammonia or nitrites. So, being in the habit of regular water changes instead of as needed can help keep nitrates from getting out of hand. Nitrates are not only food for plants but algae as well. Keeping nitrates lower can help prevent algae outbreaks.
Nitrates are no where a harmful as people make out. I won’t even bother with a water change if under 40. Real problems are 120 plus. I’ve had tanks that ran 60 to 80 for years and never lost a fish. Just my opinion and experience with nitrates.