That’s only when you actually catch it mid stream.

Once you hit space and start a new word it’s game over.

Frequently happens at the worst moment when you’re trying to mash out a complex explanation in a rushed fury.

That's not true for this situation. For the "deep" replacements more than a word back that we're talking about, and also other changes that happen without any user notification via blue text popups, there is no easy way to fix without the long process of moving the cursor.

For a replacement? Or for the next word?