I agree with your point that the harm is still done albeit less. Actually initially I also want to discuss about the pollution in the manufacturing process but deviated away from it as wanted to focus on the bigger problem of plastic pollution.

Also i was thinking that due to regulatory requirement they would have better control of air and water pollution. But your idea of solar powered manufacturing process which is even more cleaner is an undeniable fact.

Still there is one concern of whether the solar panels themselves are sustainable in long term, as mass manufacturing of them still requires natural resources and the pollution associated with it?