There's no way to set up a call connect with the user assigned to the calendar event, rather than the user assigned to the contact.
We use an automation to streamline follow-up calls. We create an event on a dedicated "Follow-up" calendar, which triggers an automation to send reminders. At the time of the calendar event, the automation triggers a call connect which makes the follow-up calls super easy.
It's super annoying to ONLY allow a call connect with the user assigned to the contact, and creates confusion in our operations. This would be life changing to get this enhancement implemented.
(NOTE: I wasn't sure where to put this, if there's a better category or existing post that's similar to this one, please comment and let me know)