Is there a way to add a specific follower automatically every time a task is created?

Is there a way to add a specific follower automatically every time a task is created?

Yes.

When using Forms to submit new tasks to a project, this is possible.
When using rules, this is also possible. → Task is added to project → automatically add collaborator

just to clarify… this rule is not available by default and I have to update my plan in order to create this rule?

Which plan are you on?