Big feet have the great advantage of improving stability. I don't fall over, even as a young man, when drunk and I have never been blown over by a strong wind.
Friends who claim to have wide feet have found Karrimors comfortable. See SportsDirect. That's all I know.
US size 13 and very flat, wide feet. Winter, I wear crepe sole mukluks (the real deal, made by First Peoples.) Summer, mostly nothing. I get by with that since I'm in the chair.