Found that the long wings helped, but that the shortest wings were useless Makes sense, the wing tip is where turbulence air flow is generated, and turbulence hinders flight. Short wings are all tip. Change of function. Short wings were very useful for transferring heat to the body, and long wings added little more. Again, this makes sense.
Heat transfer works best over short distance.
If it has to go a long distance, much of it will be lost. So a plausible origin for insect wings is that they started with a thermoregulatory function, and that got them big enough to begin having useful aerodynamic effects. In the old conventional sense, it would be OK to say that insect wings are an adaptation for flight. Our ancestors had skull sutures before they had birth. If you look at the skulls of reptiles and birds that hatch from eggs, they have sutures too.