I've been having the same issue, my world with RealismCraft, Naturalist, and FURNITURE (XP games) has not been working. I've tried playing mobile and on Windows 10. Additionally, my realms bugged out and my main world got overwritten by a duplicate copy of the Realms Celebration map and it's stopped letting me replace my worlds whatsoever showing me a "failed to find place to upload world" notification. I don't know if the worlds bugging is a separate issue but they seem aligned enough that I'll add it to my comment.
mothhsss
I've been having the same issue, my world with RealismCraft, Naturalist, and FURNITURE (XP games) has not been working. I've tried playing mobile and on Windows 10. Additionally, my realms bugged out and my main world got overwritten by a duplicate copy of the Realms Celebration map and it's stopped letting me replace my worlds whatsoever showing me a "failed to find place to upload world" notification. I don't know if the worlds bugging is a separate issue but they seem aligned enough that I'll add it to my comment.