If possible could you fix this it really makes my use of the app frustrating when I try to export. Just to be able to export something in the way I made it takes a lot of trial and error testing different amounts of zoom till it actually works. Also I like using the app but is it possible to export from the mobile app in higher resolution than just screen resolution so I can use it for something other than just personal use.
I just responded to a similar query (Canvas size) a couple of days ago and I think that response might be helpful to you:
About what happens when saving your art as an image (.png): Draw will save/export at 2048x1536 with the artwork being cropped to what’s visible on the screen (similar to a screenshot). Also, in Draw, any strokes outside of the primary canvas (the gray area) are actually considered part of the composition so any save will show that gray background because there are marks on it. So, when you save your art as an image, zoom in prior to saving and make sure there are no marks outside the main canvas.
In order to export the drawing in the exact dimension of the canvas you've selected, instead of saving the work as an image, use the Send to CC Files as PDF function. That will save a high-res, scalable PDF to the Creative Cloud Files folder on your desktop but you can also access by signing in with your Adobe ID to https://assets.adobe.com/files.
Let me know if I've misunderstood.