I’m not too sure when these spots came up. Did a quick google search and the first results says that it could be mealybugs, but I don’t see any actual bugs on the plant or in the soil. A few other answers I found says it could be cold spots, dried up water on the plant or some other plant disease.
In terms of watering, it’s watered when the soil is dry and we water directly into the pot. It’s on the windowsill so it gets plenty of sun and it’s also placed near an AC that is on occasionally (every other day for about 30 minutes to an hour)