I’m an engineer, not a doctor, however, there is no known mechanism by which RF energy damages DNA - tissue heating is the only known provable effect, and that doesn’t hurt DNA.
RF exposure standards are based on tissue heating.
As an example, a wifi access point putting out 200mW at 1 ft is less than 1/10th the general public exposure standard.
So if I installed a 100 wifi routers in my house, I could cut down my gas bill during winter? Do I have the math correct?
Sure it will (the technical term for that is "cooking"), but you need a lot more RF at microwave frequences than a wi-fi router can put out. If it raises your tissue temperature by a 1/30th of a degree F., you're right; that's not going to have any physiological effect. A mild fever is far hotter.