Using Classic Outlook on Windows for personal email, calendar, and contact management
I opened the support ticket right in Outlook with the Contact Support item in the Help menu. This seemed to get me to some guys who knew Outlook pretty well, and we talked at a high technical level right from the start.
the key is a per user key in Software\Microsoft\Office\16.0\Common\ExperimentEcs\Overrides and has an obfuscated name, but maybe that's enough to get you on the track with their support.