Any plug timer would work.
Something simple like this, although probably a bit cheaper in Jumbo or Obi:
I have all my “entertainment” stuff (modem/router, TV box, TV, AVR, Logitech Harmony hub etc.) connected to one socket and I manually switch it off at night, and back on during the day, I’m probably only saving a few rappen a night in standby usage but I still do it.
As for WiFi “radiation” - meh.