Mirror/Flip screen or PowerPoint for teleprompter

I would like to somehow mirror/flip the screen of any android tablet or just a powerpoint presentation so it is readable when using a teleprompter.
I have considered writing some kind of script that does some PDF or maybe even PPTX magic but for my exact use case it would be way better if there is some kind of "out of the box" possibility or app that does what I want.

I would be grateful for any kind of help or advice.

 

I am looking for something that works with a standalone tablet and does not require preprocessing somewhere else. If there is a solution that works with little preprocessing on the tablet itself that would also be fine.