If you want something that goes after the larvae directly rather than only starving them out, the standard one is a bacterial larvicide — the strain sold for gnats and mosquito control, in the form of granules you sprinkle or a product you soak into the water.
What matters about it, and what people get wrong:
It kills larvae, not adults. You will still see flies for a week or two after it starts working, and that is the point at which people decide it failed and buy something else.
It has to be repeated on the cycle, not once. The eggs already laid will hatch, and it does nothing to eggs. Applying it on the schedule the packet gives, for the full course, is what makes the difference — one application knocks the number down and the survivors rebuild.
Every pot in the room, at the same time. This is the other half of your reset. If you treat six of nine, the untreated three are a reservoir and the room repopulates from them. Treat all of them, including the ones with no visible problem, and including anything that came in recently.
Combined with the surface drying above, that is a real end rather than a dent.