Western governments absolutely can and do apply geopolitical pressure via measures like sanctions, tariffs and trade agreements.

Now whether they have the will to do it over plastic waste (or carbon emissions or democratic governance or human rights) is another matter, because they have only a few tools and there are thousands of priorities competing for those tools.

It also doesn't help with leverage when there is a powerful economic actor which doesn't require any of these terms as conditions of doing business: China.