I've just recently discovered this app and am trying to set it up as I develop my own GTD system.
So far it seems very flexible and powerful and I seem to be able to design the structure I need to handle Next Actions, Projects, Waiting For, and Incubate / Someday Maybe items alongside Calendar events (and also Horizons of Focus using the GT Goals feature).
TWO QUESTIONS / ISSUES / POINTS
I want to make a new List from a Task that has Sub-tasks, and for the Sub-tasks to become new Tasks in the new List. I can see that tne new List name adopts the original name of the Task it came from, but I thought the Sub-tasks would also come across as new Tasks in the newly created List but this doesn't seem to happen.
Another issue I found is that even if I have several lines of copied text in clipboard memory, I cannot "Add" tasks using the option to add tasks from memory. The new tasks never show in GT - however they do show in Reminders...
FYI - I'm using an iPhone 6+ (several years old) - iOS v12.4.7 (I can't update to iOS 13)