If you want more of something, subsidize it. If you want less, tax it. Governments are good at taxing things.
Taxing it aligns the economic incentives to produce the desired outcome, rather than banning it which leads to all sorts of distorted outcomes.
When I walk into a store these days, I can't help but think almost everything there will end up in a landfill or the bottom of the ocean.
Yes. Typically, such laws embed exceptions. But the exception list is always inaccurate.
For an example, when the EPA set fuel economy standards for cars, it exempted trucks. The station wagon disappeared and was replaced with the SUV, which was a "station wagon" configured to pass the EPA definition of a truck.
Instead of banning plastics and having an ever-wrong list of exemptions, raise the price (via taxation) so other materials become cost effective.
Great book on this very topic!