This video has some tips that I've found helpful on my 13" Macbook
https://reaperblog.net/2017/08/max_edit_space/
also, you can run in fullscreen mode to the hide the menu bar.
In the mixer there is an option to show multiple rows of tracks, I don't really like it, but it is an option.
The Default 3.0 theme can fit more tracks on screen as well.