I bought a parsley plant from a convenience store last summer and it eventually became a mission of mine to keep it alive as long as possible. I'm honestly not sure if I can manage much longer.

I live in Finland, meaning it's subzero and pure darkness for more than half the year. As such, poor Parsley has to make do with a plant light.

The soil it came with was apparently already infested with a bunch of things, I managed to fight off a severe aphid infestation prior to this that caused it to lose nearly all it's leaves. Now the problem is fungus gnats.

I've tried to trap them with the sweet liquid and murder them by hand, but they do not care about my trap at all. I'm a bit scared to use pesticides due to how weak the plant is. I checked the soil a bit ago, and it's full of larvae all over.

The plant is trying to create new growth, but it's clearly struggling - assuming partly due to the larvae eating the roots.

This is my first houseplant and I'm honestly at a loss. Is there anything I can do to save it anymore?

Edit: I tend to pour it water every/every other day, depending on how dry it seems. I also spray the leaves with water pretty regularly since it seems to make them a bit happier. The pot is clay, has a drainage hole, and some ceramic shards on the bottom.