On the flip side I have thought about getting into reverse osmosis as a side business. Afaik reverse osmosis does remove microplastics and most other harmful things from tap water. And on top of that it makes better tasting tea and coffee imo.

On top of that, reverse osmosis can get drinking water from sea water. It seems that the feasibility of reverse osmosis is directly related to available energy, but wouldn't that be a great use of excess produced electricity vs. storing in batteries?

Of all the things humanity should be looking to make technological improvements in reverse osmosis, or even better solutions (electrolysis?, distilling?), should be pretty high up.