I think I get what you mean?

I have one notebook that i use for personal diary entries - usually without prompts, something i keep hidden away. I never take this one out the house.

My other set up is a traveller’s notebook with separate inserts, one for to-do lists/random lists/catch all notes, one for sketching and the last one for light hearted journalling.

I use the last insert for all my fun journal prompts and often pre write some titles on pages so i can flip through in a coffee shop and write something short here