The dumping in the ocean part is an issue in countries with under-developed waste management infrastructure, not something inherent to plastics.
I think there may be an angle here, but it’s distracting to so drastically minimize the environmental impacts
Glass is extremely carbon intensive to produce, and it weighs an enormous amount meaning a greater carbon footprint to ship products from factory to table. Not to mention it is impractical for goods like freeze dried potatoes mentioned above.
Steel cans and other metal packaging is lighter than glass, but also heavy, and does not lend itself very well to frozen foods, but mainly to preservatives. It is also carbon intensive to produce and lined with plastic. Glass and steel are recyclable, but this is carbon intensive and only works when people are educated enough to recycle and then the infrastructure exists in the first place.
To cap this off, microplastics are not yet even proven to be harmful. The scientific literature is "no" at best, and "inconclusive" at worst. It is not some proven hyper-carcinogen that many laypeople get the impression it is.
I think a lot of people have some sort of pavlovian response to the word plastic done by 25 years of fair and unfair media coverage, without thinking about actual plausible alternatives to it.
"Plastic is bad, we should use X" is an interesting comment worth exploring.
"Plastic is bad" is a statement. Yes, everything in the world has pros and cons, but stating cons in a vacuum isn't insightful.
The main issue is whether it makes it to the landfill in the first place, but this isn't particular to plastic. .