Hi @dennis.raulien
Thank you so much for reaching out to the Zoom Developer Forum, I am happy to help here!
Unfortunately, there is no way to add Collaborators to the Server to Server Oauth app nor to the Webhook-only app.
Since the Server to Server is tied to the user and the scopes available for each user are related to the permissions they might have, it is not possible to add collaborators to it.
I will make sure to bring this feedback to the team to see if they have any input for you!
Best,
Elisa