Some leaves are showing small burnt spots and slig...

Lol 😆 Frank's hot sauce!

Cayenne pepper never worked for me. Perhaps the gnats here are more resilient to spice.. After I stepped my game up to habanero peppers, the gnats died left and right. By the way, don't use ghost pepper. The plants don't enjoy that at all 😓😓

Gnats, wah, could be worse, could be spider mites. You will need yellow stickies they are visually attracted to bright. Isopropyl alcohol can be effective as it instantly kills little blighters. Won't kill eggs you will need to put plant through a drought period long enough to leave top 3"4" to dry out leaving eggs no place to hatch. Even then I feel there is always one who survives. Add equal parts water + Isopropyl half a tsp o cayenne pepper and a squirt of dish soap. Or Copper fungicide can be used to treat plants with fungus gnats and to prevent the spread of disease. A root drench is more effective than spraying the leaves. Lots of fun. Good luck.