AsNoriuanswered grow question 16d ago Think its thrips, despite you calling them gnats. Gnats fly, thrips hide underneath of leaf, could be huge problem.
When i met them first time, i noticed at start of flower. Ladybugs and few natural predators sorted issue, but my harvest was 20-30% lower than i would expect.
Sort it asap, have sticky traps all around grow area as prevention.
Good luck !!!