3M and Dupont deserve the death penalty for it and should've been dissolved completely for crimes against humanity.
I've lived in communism and it was exactly the same. Pollution beyond any reasonable levels, testing chemistry on products and people, rules and regulations coming from government and faceless bureaucrats... The result was the same, but instead of corporate greed the reason was lack of any interest and foresight.
Well regulated capitalism is probably best equipped to deal with such. Whether ours is well equipped to deal with this is another question.
But the thing is capitalism is a tremendously powerful machine, so it's really more dangerous than an unmotivated Polish bureaucrat. The Soviets may have drained the Aral sea but capitalism has poisoned the entire planet (with TEL even before PFAS).
I had the same thought about demineralised water, you can get more expensive models which remineralise the water after, but it looks like it's not actually that important health wise because you get the absolute vast majority of your minerals through food, not water. And remineralisation is mostly for taste rather than health. Though I don't find the demineralised water tastes bad, but if you're used to drinking hard water it might be different.
Personally I would prioritize water filtering for PFAS over microplastics worries if you have limited budget to start changing consumption patterns.