You were in the Dev Insider's Channel on Windows 10. It seems you chose not to install the first release to the Dev channel of Win11 when it was offered, as it was optional. But you failed to leave the program at that time. Since it's already begun to download 100, it will keep trying to do so, and now you only have two options: Delay it for up to a week, and then accept your fate... or do a full re-install of Windows 10.