Can't get rid of second calendar

Whenever I switch to the Calendars widget from the navigator pane on the left, I always see my calendar plus a calendar that lives in Public Folders.  I can remove the Public calendar by unchecking it in that same navigator pane (it appears under other Calendars) but if I then switch to the Inbox and go back to Calendars, it's checked again.  I've tried everything I can think of:  resetting my view, exploring File | Options, combing through the Registry for the name of the offending calendar, rebooting.  Nothing works - the calendar is always there and I have to manually turn it off every single time.

Any thoughts on how I can get rid of it?  If I right-click, there's an option to Delete Calendar, but I'm pretty sure that would delete the calendar from Public Folders, which would be very unpleasant as that calendar manages staff schedules for the entire team.

Microsoft® Outlook® for Microsoft 365 MSO (Version 2208 Build 16.0.15601.20644) 64-bit