I disagree that undo and redo are the only two actions needed to support this behavior. For example, if I’m performing the following three actions:

- insert A

- insert B

- insert C

And then I undo, I would expect to be be back at having AB. If I then undo, I would be undoing my undo and have ABC. Then undoing again would get me back to AB. And I remain in this 2-cycle.

Instead I propose the best solution is to be able to “step out” of the editing experience and see your history in a separate UI, and be able to choose a specific past version to revert to. This revert would be an atomic operation that could then be undone.

This is how most versioned consumer systems I know of work today (e.g. Google Docs, Figma, MS Office) and it feels intuitive to me as a user.