The slideshow button is a split pill, you can open it there where there is this tiny up arrow that opens up a drop down menu. But on tablet it probably doesn't do what you want it to as it was built for multi-screen use on the desktop.

I'll have a think on this tonight and I'm sure we can do a tablet speaker notes mode.

I tried out the speaker view now that I'm on my laptop, and that would be great for someone actually giving a presentation, but since I'm just viewing it, it's not quite what I want. (For one thing, the animations don't happen.)

I just want to see the speaker notes while looking at the slides.