Show Presentation screen on external display while phone is locked

Question

I am writing code for a Cat S22 Flip that would show notifications on the external screen. I implemented this as a service that starts after RECEIVE_BOOT_COMPLETED. The service presents a Presentation screen with some content (time, date, battery, etc). This works fine when there is no screen lock. When there is a screen lock I only see a dark screen. How can I implement Keyguard to show this Presentation on the external screen when the phone is locked?