Many factors are at play here. As Andrew (Guessed) said, typing speed may be one such factor.

However, I vaguely recall that there was a specific issue that caused Undo to do only one character at a time. I don't remember the details at the moment, but I will post back when/if I can find out more. :-)

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Stefan Blom
Microsoft Word MVP

Microsoft 365 apps for business
Windows 11 Professional