Hello again @ROGERBSP !!
The Camera folder has all what you need to do what you wanted!
Inside the BP_CamManager you can find all the variables and the logic to set the camera on a predefined height independent from the player Z position.
In the function Blueprint Update Camera you have these blocks:
And each chunk of code is commented to understand what it does. This should help you a lot!
Hope you can make it work! Let me know if you need more help.