Read-only view is very limited; no subtasks (unless those are homed back into the project to appear as top-level tasks as well), and no setting to change.
Not directly, but that’s the start of an approach that I cover in detail here:
Effectively, you could use a single-select Customer Facing custom field with a single value of to trigger a rule to multihome such tasks to a paired external project of just those tasks. See my post above for details.