Ok, so this time, I used fly spray again. But it was because I saw a bunch of gnats at the bottom of the tray, where the plants' water drains out. So I only used fly spray on the tray, and now theres a bunch of dead corpses of the gnats at the bottom of the drainage tray. Also, I think the plants may be getting worse:
See, the picture I took today compared to the picture of that same leaf I took a few days ago, it looks way worse In my opinion (look at the edges, the leaf looks more sick than it was before!) In addition, I took some other pictures. One shows that the bottom of the tray is where I sprayed the fly spray, so there are dead corpses of gnats. Another one shows that the leaves are kind of looking a bit more puffy than they were before (I think they are droopy, I haven't watered since yesterday so I'll give them a tiny bit of water now)
Also, today I didn't water them since I am giving them a moderate amount of water every other day (in the early morning around 7 AM so it evaporates or dries off)