thank you Jean! Usually just stick my finger in the dirt to see if the top layer is dry and then water it if is! To water I stick it in the shower and fill it and let it drain a couple times. At first I was using plain old tap water straight from the faucet but then I read that the chlorine could be harmful so I started leaving the water out over night and doing it that way! It's sitting across from a east facing window it gets some pretty bright sunlight every morning until about 12-1.

The pot is placed a few meters from direct sunlight ==>>> its indoors.. it gets NO direct light ... mostly because there is a window in the way ... and its simply too far from the diffuse light from that window ... the third pic seems to show very good new growth ... why do you say its brown?? ... how about a closer pic ... its going through some stress from moving it from one place to another ... all plants shed older leaves ... annually.. it can be increased due to stresses like moving it ... i think you are on the verge of loving it to death ... try to chill a bit.. and settle in.. and try to get it closer to a window... there is a houseplant forum ... where you can learn all about such ... ken

To me, this looks like some kind of bacterial blight. I would suggest cutting stems of infected leaves, cleaning the scissors in between each cut and using an organic fungicide. My monstera had something similar.

Yes green balls are fertilizer. you said no repots, so Im guessing plant is still in its original store soil. Those are usually way too water retentive. A lot of people on here either use Al’s 5-1-1 mix for tropical or soil mixed 50% w/ 50% sifted perlite or pumice. 5-1-1 has 5 parts pine or fir bark, 1 pt. Sifted, coarse-grade perlite & 1 part peat. The issue w/ your Monstera looks like bacterial leaf spot from too wet soil, but I could be mistaken.. others on here may be better at diagnosing. These grow under trees & climb their trunks like a vine in the wild, south of the equator. Your water & sun accommodations sound good, as long as you keep it where it’s at, that light would be similar to what it wants, which is part shade.