You're correct, it's sometimes necessary to pull up on the pane containing the suggested routes, as the "draw your own route" option is at the bottom of those and may not appear. I'm glad you were able to find it and hope you enjoy creating some custom routes!
Thanks for your post! The Strava suggested routes in the Mobile App are looped courses, however you can draw your own route that goes from point A to point B. Just look for the "Draw your own route" option at the bottom of the Route page on the Mobile App. You can also make edits to the Strava suggested routes and save them.