The versioning built into Microsoft Office....it isn't that useful. Not after you have experienced what real versioning functionality (backed by a decent versioning software like Git, Mercurial, SVN or even the venerable CVS and RCS) can do. Especially with text-based file formats (like .txt, .adoc, .md, .php, .c, .bat etc.) this works amazingly, once you get your head around the workflows such systems demand. However, for binary blob file formats (like .docx, .xlsx, .pdf, .png, .jpg etc.) such software is barely usable.
Still, Ath is completely right in stating that such functionality is major overkill for simple Undo's (Control + Z).
Yet the text
Do and undone with flexibility is better because we don't know how many keystrokes control+z are necessary until reach the target...
indicates to me that Contro might actually be in the market for a full versioning system. Git is free to download for Windows, Linux and Mac. And there are many free and/or open source Git clients available. Fork, GitExtensions, TortoiseGit etc. allow you to work much easier with the Git versioning system. You could even implement a web-interface for Git. One the more (in)famous ones is GitLab (Linux only!). Gitea is simpler to setup and maintain. It is also much more resource-friendly when compared with the GitLab software.
All of the above does require a good read of the installation instructions and Git clients come with their own manuals as things can get complicated quickly. A good grasp of concepts is essential before embarking on this route. Yet, if you mainly work with binary blob file formats, setting up a versioning system will be almost for nought anyway. But, as Contro mentioned in his post, he was working with PsPad, which is an editor for text-based file formats, so going for a Git setup might prove useful.
Git clients usually have a differential viewer built into them. So it is pretty easy to see the which file is needed to step back to. And if you are not satisfied with those differential viewers, you can get better ones for free as well. WinMerge would be one of the options. Git clients are familiar with this one and send the content you wish to review directly to that software without human interaction. Software like WinMerge also have more/better features for editing and marking differences between files.