Q.Ming Aralia With Black Spots
I think my Ming got fungus gnats?? I’ve treated it twice with neem oil, but have lost much of the growth at the top. The second treatment, I went in with tweezers and tried to remove the black spots and cut off the leaves that seemed corrupted and now it’s dropping much of the growth from the top part. I have it sitting on the outside of a grow light for about 12 hours each night… is this too much light? I feel like topping it but I’m scared of killing the entire plant. PLEASE HELP this is a propagation from a Floridian outdoor that I relocated to NC. It was healthy until I noticed the gnats and then black spots, oh and then my surgery seemed to be a bad thing. Anything helps!

Certified GKH Gardening Expert
The gnats won't, usually, cause any issues. Overwatering will, though. Likely, they are looking for infected and rotting roots from wet soils. They don't like to be outside of the soil, so seeing them flying around means that the soil is highly saturated, even too much for them to remain there.
The black spots that you are seeing will, likely, be the reproductive stage of whatever is infecting your plant. Unfortunately, your photos did not come through, so I am unable to see the damage.
You will need fungicides, and to be sure that your container allows for ALL extra water to leave, freely. If your container does not have drainage, where you can remove any extra pooling water, then you will need to change containers.
Here are some articles that will help:
https://www.gardeningknowhow.com/houseplants/aralia-plants/polyscias-fruticosa-ming-aralia.htm
https://www.gardeningknowhow.com/houseplants/aralia-plants
https://www.gardeningknowhow.com/garden-how-to/info/using-fungicides-in-garden.htm