Arthurmorgan,I have a Ring door bell and a Ring Camera and the same thing is happening to me.I live in Washington State and during the cold weather the cameras will fog up.There is no fix and it sucks.
I found that rubbing soap on a clean microfiber cloth and passing lightly on the lens helps. It lasts quite a while depending if it rains. Apply as needed, has not harmed my lens at all. Hope it helps.
A bar of dry bathing soap dry or just a dab of water. Make sure it's not an exfoliating soap it can scratch. Rub on softly and with the ring active on your phone rub until clear not off. If you do it at night you can tell with the street lights or neighbors lights they look a little stretched but the video and view are perfect. We had 20 degree weather again last night and it worked like a charm. Good luck.
Easy fix if the fixture is above the ring at night when you turn the light on take a small L shaped piece of card board or stiff paper and pin or tape it just above the doorbell on the house. Don't place it directly on top as it will affect /block the motion sensor. Then take the card board off in the morning.