I think you're wrong. I did extensive research on this prior to purchasing a home recently and the general consensus I found is that you need a pretty advanced water filtration system consisting of carbon + reverse osmosis filtration that requires yearly servicing. Some water companies do this, but most probably don't. You can also have a system installed in your house.
Your standard Brita filter doesn't even come close to filtering these chemicals.
This is not true. The NSF/ANSI standard 53 specifies that filters must remove PFOS/PFAS[1], and both reverse-osmosis (RO) units /and/ granulated activated carbon filters are certified under that standard. Granulated activated carbon filters are the same kind found in Brita filters.
For example, Samsung RWP70010TWW is a refrigerator filter approved[2] for filtering PCBs, PFOS, and PFAS, as well as a whole host of other things. You don't need to spend ten thousand dollars installing a reverse osmosis system to get clean water.
AFAIK, distillation will not remove volatile organics that have a lower boiling point than water(well, theoretically you could do some fractional distillation technique, but its easier to just run a carbon filter).
Deionized water is often acidic as protons are introduced to replace the other ions. Co2 also dissolves immediately from the air forming carbonic acid. Regardless I don't think it's bad for your teeth it's not concentrated or buffered.
Need to treat it with minerals though, as the pure water will be acidic and strip your teeth of them otherwise.
It is pretty overkill, but if you want pure water...