Android iOS: fixed Sidebar

I would like a function for the Android and iOS versions that allows the left sidebar to be fixed.

Reason: When I have to look through various notebooks and files in them, the sidebar keeps folding away. I would be happy if I could pin/freeze it when needed. I work less and less on a desktop PC, where the sidebar remains permanently available. It would be great to have that on tablets too when needed. Thank you very much.