Your only answer here is doing water change.
We can only measure ammonia, nitrite, and nitrate. There are actually thousands of other pollutants in a aquarium that comes from food and fish waste.
Think of nitrates as the measuring stick for the total amount of pollution in your tank.
If you use plants to reduce nitrates, then basically you dont know how bad your water really is. A well planted tank may show nitrates of 10, but the number could be way over 40 with time.
If you do your weekly water changes without plants and nitrates are stable, then it would ok to add plants for the fun of the hobby. Plants are good for taking out the pollution, but they do not mean you can do less water changes.