I fished for many winters using either a hardy Featherweight or a CFO III as my reel. When I say winters I lived in Pennsylvania and fly fished through the 1979 - 2004 seasons using those 2 reels. back then I learned that if the expected high wasn't to be much over 30* for the day the ice in the line guide thing would be a significant problem. However I never had a reel freeze up.
There must be something at the root of the problem; are you allowing the reel to be submerged, reeling in the wet fly line repeatedly? As for allowing a reel to be dipped as I see when I look at pictures of people with fish, I never did that. Many fellows figure that 'hey it's a reel' so what the heck but i only remember dunking one once by accident. If the reel had enough water on & in it to freeze solid, then it has to be getting wet somehow. Eliminate the source of the water and you'll eliminate the problem
I was not an older man before I realized that trying to fly fish in freezing temperatures didn't make sense and wasn't that much fun. That's only my opinion and I don't mean to disparage you if you in fact enjoy it.