I bought this plant about 4 months ago. I repotted it form its original nursery pot to a larger nursery pot around 2 weeks later. Sometime after that, the bottom leaves started to get brown on the edges, but they didn't fall. I watered every 6-7 days, checking the top 2 inches of soil first. Since I also started to get fly gnats in the house, I decided to repot the plant once again into the same nursery pot but loosening the roots of the plant (they looked fine to me, but I'm no expert) and changing the soil. The previous soil looked too damp, so I also added more drainage holes.
It's been 2 weeks since that, I've been watering every 7 days and it's near a window that provides bright indirect light. It's getting worse and it has lost a lot of the bottom leaves.
What should I do? Is there anything that can help to save it? Is this a watering issue or it can be a disease?
Thanks so much for your help!