Turn a selfie button into a slides clicker (android) using external keyboard helper pro to intercept the button and remap it to a more useful command.
Pair with the bluetooth remote
enable the custom keyboard in android settings
advanced settings > keyboard mapping > customize keyboard mapping
Map keycode 28 to page up
map keycode 115 to page down
Open an input box and change the on screen keyboard to "external keyboard helper pro"
Now start sheets.
Hopefully pressing button 1 should map top page up and this should go to the next slide.
Pressing button 2 should map to page down and go back a slide.