In the phone world, the jump in capacity that modern phones have from my 4370mAh battery in my A71 is negligible. They haven't increased power density much because that way leads to fires and lawsuits when users bend or otherwise damage their ridiculously fragile phones
My point was, if modern phones had the physical space that my phone + case has, they could have a bigger battery, and that bigger battery would then power all the hungry, hungry electronics.
This is the hard part. Modern techniques can detect just about anything in anything, down to parts per billion or less.
So we all have measurable quantities of PFAS , radioactive materials, arsenic, plastics, endocrine disrupters and so on and so forth, but there are very few actual hard numbers as to what levels are distinctly harmful and what levels are just "something else will kill you long before this does".