I recently migrated from Office 2016 to office 365 and some GUI-functions seem downgraded as a result. In Excel 2016 I could do: Data -> Connections, a window would open, I could select them all and delete them. In 365, something to the right opens and I can only delete them one-by-one...
To illustrate I attach screenshots of how one manages data connections in Excel 2016 vs Excel 365.
Kind rgds,
Jaron