Compatible with Google calendar, Outlook calendar is NOT supported (use my appointment flow with BUSY status instead)
The flow sets ringer mode to vibrate during do-not-disturb appointment and changes back to ringing when it ends.
Just put the tall letters "DND" in the note field of the Google calendar appointment.
Only appointments flagged with "DND" are recognized. All other are ignored and ringer mode is not touched.
With that it is your choice on which appointments auto vibrate mode is needed.
Click on Calendar URI in the first block (await DND Event) and select your desired calendar.
Rate and review within the app in the Community section.