imo most people just underestimate the sheer amount of plant matter required for your plants to filter your water naturally.
I have a 10 gal that i absolutely PACKED with plants, i mean, it looks like a forest in there and have gone a month without a water change with little to no algae. Although i did start with only shrimp and then put 6x danios in there after 3 months or so. Using seachem florite black as a substrate too, which im pretty sure is inert.
Then i also have a 33gal packed with plants that has tropica aquasoil, co2 injection, oversized filter, maybe 16 neon tetra sized fish and i get algae after one week without a water change and the plant growth isnt anyway near as good. Its weird.
Its like a fucking dice roll i swear.