Understand if user needs an undo and redo button always visible on the UI

So we have an app where users can undo or redo their changes using the keyboard shortcuts Ctrl + Z and Ctrl + Shift + Z. There is no button available on the UI for them to do this. Only the keyboard shortcut.

What we need to know is if the users are having trouble undo-ing and redo-ing their work. The app has been live for awhile now and so far none of the users have complained about not being able to undo/redo an action.

From our tracking data, we can only tell how many times the shortcut keys have been used and the number of total sessions during a time period. The number of times the shortcut keys are used is low.

What I want to ask is, what data do I need and how do I analyze if:

  1. Users are able to undo/redo their actions when they need to
  2. Users are unable undo/redo and just go on because they think it's not a feature
  3. The low number of the shortcut key usage is because users don't use undo/redo that frequently.
  4. The low number of shortcut key usage is because they don't know undo/redo is there.