That can dilute what's circulating in your bloodstream, but not what's already accumulated in your brain, lungs, liver, kidneys, and probably some other organs that weren't studied yet.
Not necessarily. I visit our local medical vampire every 3 months to drain a pint due to high levels of ferritin (hemochromatosis issues). I asked what they do with the blood. They destroy it by ashing it. The tech said they do this with any blood drawn from someone with a known disease state. So if phlebotomy becomes a common treatment for PFAS loads, I'd guess the draws would be destroyed. I hope.
https://pmc.ncbi.nlm.nih.gov/articles/PMC8994130/