I think like PowerPoint, it'd be good to be able to collapse the purple toolbar (that sits above the pen tools). It honestly takes up a lot of vertical space and is unnecessary for the entirety of a notetaking session.

We normally don't need to access the notebook name, tabs, recording, share, etc. immediately and therefore it is a waste of space for it to be visible sometimes.

It should be easily collapsed, and some essential tools like back and forward could be moved to the writing tools row that should be the one to only show.

On an 11" iPad Pro, removing this row might finally allow you to actually see an entire A4 document nearly edge-to-edge (excluding the writing row)