Accept meeting invitation RSVP with application access

Hello

My question boils down to:
Is it possible on an event to set RSVP to accepted for a meeting attendee using application access only?

I do not really mind if RSVP mail is deleted/disappears or not - as long as the calendar event is updated. But maybe they are tied together?

Context:

I am using graph API to create calendar events and subscribing to updates to keep my application and outlook in sync.
I have a feature in my application that allows meeting attendees to accept/decline an invitation - they can also choose to accept/decline in outlook RSVP mail or calendar. I would like the end result to be exactly the same in both systems.

So i have tried to update meeting attendee with response status 'accepted' using graph API - and also tried to set responseRequested: false. The event is set as markAs: busy when created.
However the events remains in tentative in the attendees calendar - only change is that organizer can se accepted in the dialog hovering the event in attendees shared calendar - and 'You asked invitees not to reply' - or someting similar, when opening the event dialog.