It could be monologue or dialogue, but it should be less full of verbal "syntactic sugar" than NotebookLM podcasts. More to the point, more detail-oriented, can pronounce math.

Can pronounce math is the real showstopper for me. Last time I tried, NotebookLM would try to say the TeX out loud. Like underscore dollarsign...

It's been sometime I have been using an app called nouswise. I switched right after they added nblm notebooks in Gemini. I knew they cannot stand another app competing with their flagship. But anyway, it do have audio recap and it definitely have way less of "syntactic sugar". I haven't tried but because it's agentic you can ask it to generate a monologue for you. But I assume you should be in deep mode. I so far only used the side bar for this.