I can't create a new event from inside Overlap on macOS. It all goes wrong, sadly. Images show:

(1) I have authorized the connection to macOS Calendar

(2) This is what happens when I try to add an Invitee

(3) Then when I click Save (no invitee), the button goes gray and nothing happens

(4) So all I can do is cancel out without setting an appointment

(5) Maybe it's because this apparently is Overlap for iOS (this is the prepopulated text in the notes field of a new event)