Seedleranswered grow question 7 months ago its certainly a kind of bug bot not a gnat. gnats in the soil are quite large white larvae, not little bugs. but i can't tell what or if harmful. but i can give you a tip: neemoil. its non toxic towards the plant or human but it will stop insects building chitin which makes them not a threat anymore. it worked wonders for me!
gl, i hope they did not ate the whole crop in those 3 weeks