So, there is some interesting data on this in the data. Most of the North American waste comes from central America and the Carribean. The US and Canada combined are responsible for .27% of global plastic emission. Guatamala emits .73%, Panama emits .53%, Haiti .71%, and the Dominican Republic .64%.

Banning plastic bags won't do anything here. This is about countries not having sufficient waste disposal systems. If you want to have an impact on this, don't push for bans on plastic bags and other single use plastics. Donate to NGOs that help build new waste management systems in affected countries and push for federal grants to such organizations (if in the US).

As a side note, SUP bans actually have a number of unintended negative consequences, and it is not clear that they are even a net positive for the environment. Depending on who you ask, the environmental impact of such bans ranges from significant to marginal, and CO2 emissions from plastic bags is likely far better than alternatives.

Source for C02 claim: https://news.climate.columbia.edu/2020/04/30/plastic-paper-c...