Yes. The physics of radiation and it’s medical impact is the single most studied subject in the history of such things, thanks to untold trillions sunk into research and development of nuclear weapons.

Ionizing radiation cause DNA damage and cancer, the damage level can be both computed and measured.

Non-ionizing radiation only causes temperature increase - lightbulb and microwave alike. The only difference is how deep the heat penetrates, and how many watts are pumped into the subject. The WiFi router is damaging in the same way as a very small lightbulb, and much less so than sitting in the sun.