Plastic pellets are a visible pollutant on beaches. I have not seen any evidence that they're a particularly harmful pollutant. A single 20 tonne containerload of plastic pellets can leave a visible residue on hundreds or thousands of beaches, but the 15 tonnes of CO2 emitted by the average American every year is entirely invisible.
https://static1.squarespace.com/static/5ff6c5336c885a268148b...
Additives can leach out of plastics and enter the food chain, but pellets lost at sea are a completely insignificant factor because the total volume of waste produced by this route is so small. The majority of marine plastic is either post-consumer waste dumped in rivers in developing countries, or fishing gear that is lost at sea. If you're really worried about this, then you really need to take it up with the government of the Philippines and the global fishing industry.
Nurdles are everywhere... https://www.nurdlehunt.org.uk/nurdle-finds.html
I for one love nurdles!
(A similarly nihilist viewpoint comes from the people who pontificate that "the planet will be fine, it's humans who will suffer". Sure, if by "the planet" you mean "a lump of mass orbiting the sun". Low bar for your ethical framework.)
Or highest. Puts overall species diversity ahead of the future of a single species (us).
Natural selection is a scientific concept and process. When people hijack these concepts for social or political aims, it's no longer scientific, and it's something else entirely.
But we are living in a mass extinction event. Billions of crabs died. Bug population has collapsed. Biodiversity has nosedived.
Humanity hasn't suffered yet in terms of total population, but that's because we're able to adapt our environment accordingly. That said, we will see famines and scarcities in our lifetime. Hell, we already do, but it mainly presents itself in day to day life (in "the west") as some products going out of shelves (the UK having supply problems due to brexit / long border queues) or prices spiking (e.g. produce from Ukraine). But worldwide we will see more of that.
As for (micro)plastics, IIRC we've yet to determine the full impact. But we know these nurdles break down into microplastics over time due to UV exposure and the like, but they don't disappear completely and find their way into everything. We'll only know the full impact looking back in a few hundred years.