Well, I turned off Windows Media Player, which I very rarely use compared to Winamp, and for some amazing reason MP3Tag now appears twice in context menus for .mp3 files. (Windows 10 Professional v21H1)
@Zerow I have installed (and since uninstalled) the x64 version.
There is now ONE "Mp3tag" entry in the context menu when an MP3 file is right-clicked.