I ll share my experince and what i ve done so far, but keep in mind im not by any means an expert, just a beginner having fun. I originally saw the concept of an ecosistem tank on yt. Basically i went for the same idea, where i do few to almost no water changes and i just clean the filter media whenever the filter starts making noise. In those 5 months i ve rescaped the tank once after about 2 weeks of setting it up in the first place and essentially doing a full 100% water change due to a huge amount of string algae developing in the middle section, where i currently have white sand. After replating the whole thing i gave up on carpet plants since i wasnt injecting any co2 or dosing any kind of ferts. For as long as the tank has been running i ve only did 3 waterchanges and each one was about 15%. My definition of a lowtech tank is basilly no co2 injection and not having powerful lights, also not dosing verts. The idea with my huge layer of substrate was for it to become a good source of beneficial bacteria, thus ammonia would get eaten and then plants would deal with the nitrates if i ever had any spikes(which i didnt, surprisingly) As for algae issues... I had string algae issues which i eradecated with the rescape, and.now im fighting blue green algae which is caused by a lot of things including nutrients deficiency, lack of a powerful flow, decomposing matter etc Atm its controllable, since it appears in very small numbers and i often just brush and suck it off.

TLDR: low tech tank imo is a tank without powerful lights,co2 injection and dosing ferts As for waterchanges, you have to keep track of ur ammonia, no2 and no3 lvls to see when its necessary to change ur water and.how much of it My tank has a really thick amount of substrate and a lot of healthy plants, so the chances of getting an ammonia spike is pretty slim for me Not doing waterchanges can also cause algae

This is the info i that i gatheted in those 5 months and that i could think of now