Most plastic pollution in the ocean is directly related to shipping and in particular fishing[0]. Nothing I can do individually can address this, change must come from World leaders and industry bodies working in good faith across international borders. They all know this is happening, they all know measures that could be taken to address it.
Much of the framing of climate change and pollution as individual responsibility comes from large industry bodies themselves, who would much rather you feel guilty about it personally rather than wonder if they might be to blame.[1]
[0]: https://www.theguardian.com/environment/2019/nov/06/dumped-f...
[1]: Plastic Recycling is an Actual Scam | Climate Town https://www.youtube.com/watch?v=PJnJ8mK3Q3g