Lets have a hypothetical conversation. Lets say such nefarious technology does exist, would it be possible short of amputation to remove the quantum dot tattoo once placed in the body ? https://www.science.org/doi/10.1126/scitranslmed.aay7162

No, but amputation would be a bit extreme. Quantum dots simply fluoresce when excited by a wavelength of light. They would have to be read directly with a laser and a detector pressed to the skin and would only be in the near infra red range.
Now what brings up this hypothetical conversation?
I don't think we are likely to agree about the utility of frequencies as a coherent disease treatment. I frankly do not believe that any have been sufficiently demonstrated to have merit.
I do agree that increases in technology are likely to increase disparities caused by wealth differences, and it is quite easy to forecast some rather nasty future scenarios if this occurs unchecked.