Insulation between external roof rafters

Hello everyone

First of all, thank you for your help
Our new building finally has a hip roof....

The beam layer of the interior ceiling rests on the ring beam. The collar purlin lies on the beam layer. This creates a gap between the ring beam and the roof from the outside which needs to be insulated...
I have now closed the gap with OSB boards. I wanted to glue / screw the insulation onto them.
Now the question...
Is the insulation board that is installed between the exterior rafters attached flush to the rafters or is there an air gap left and filled with foam?
My concern is that the wood moves, pushes the insulation board away, and causes cracks in the exterior plaster.

Thank you for your proposed solutions and I hope I was able to express what I mean.

The insulation boards are glued. Without external insulation in the cavities between the rafters. With external insulation, the crosswise laying of the insulation boards is stopped about 1.5 meters below the roof, then the insulation boards are glued upright up to the underlay membrane, only then the gaps are finally insulated. The angle of the roof pitch is transferred to the short side of the insulation board, cut with a styrofoam cutter (hot wire cutting device), pressed up, and the position of the rafters is marked. Then the space for the rafters is cut out of the insulation board. Pressed up and glued to the wall, flush with the lower boards. Since it cannot be cut perfectly, the gaps inside and outside are filled with construction foam, but no construction foam on the underlay membrane. Construction foam (just like white styrofoam) is not UV-resistant and should not be exposed to the elements untreated for too long.