OS: iOS 13.3
Model: iPhone XR
iOS 13 appears to have fully removed the ability to adjust size and overall placement of all keyboard apps that I have tried. OneNote got around this issue by allowing the ability to place text anywhere on a note that wasn’t preoccupied, regardless of where it may be in the overall document and allowed moving the document around freely by using a drag and drop approach.
Dragging Joplin up doesn’t solve the issue and adjusting the zooming of the screen and font size hasn’t either. It seems to be a UI issue with the keyboard.