Thanks for the links. Certainly, when I became an atheist, the hardest thing to come to grips with was the loss of community. There are lots of little communities--WOW guilds, school sports teams, etc. But there's nothing like a universal religion which everybody belongs to.
https://www.sundayassembly.org/ is the closest organized effort I've found, besides local community groups around volunteering, philanthropy, and hobbies/shared interests.