Q.What Is Wrong With My Agleonema? Over Water? Underwater? Fungus?
I just reported from the department store into fresh soil and pot. She is in pretty mild indirect sunlight, could that be the problem?

Certified GKH Gardening Expert
These plants are almost unkillable with the exception of overwatering. This will make quick work of the plant. Be sure to let it dry out, very thoroughly, between waterings. This plant will tolerate drought conditions, quite well.
https://www.gardeningknowhow.com/houseplants/chinese-evergreen/chinese-evergreen-plants.htm