Try this: https://www.craftylittlegnome.com/fungus-gnats-houseplants/
A good insecticidal soap spray will work, too.
I spray all my houseplants every other week with Young Living's Thieves Cleaner and I have not had any issues with bugs
A botanist I follow recommends using Dr Bronners to make a soap spray. A few squirts of Dr Bronners castile soap in a spray bottle of water and spray on the underside of the leaves.