For out of the box Web App Builder in AGOL:
How do you use the Incident Analysis widget's drawing tools with an iPad Pro and an Apple Pencil (2nd generation) and Magic Keyboard to "Double-click to complete" a line or polygon?
Single tap to begin and add segments works but the last step to Double tap using the Apple Pencil or Track Pad does not work.
It works fine using a finger.
Logged as bug, 000135128
Workaround: Use your finger to complete polygons / lines.
Note: This worked with Pad Pro (iPadOS 13.6) and an Apple pencil (2nd Generation) but not using 14.1