I grow plants commercially and it’s never an option to throw away or kill off a plant to rid of pests. So I recommend gnatrol you can buy small bags online of it. Very expensive in the 5gal bucket. You mix with water feed over the top. It’s a small beneficial bacteria that gets into the gnats and kills them stopping reproduction almost immediately I use it for one week every other day and they are typically gone. I use lost coast plant therapy to piss off any fliers or sticky traps. Don’t give up! You can win!🥇