This. Also, the requirement to get all unique files (guesses OP means personal files) can be hard. In theory, OP should just copy out C:\Users<username> but this also includes a lot of junk from apps. And often, it makes no sense to copy everything, like Chrome, where you’re only interested in a small part of the data and not all the cached objects. Chromium based browser profiles are huge, often with hundreds of thousands of files. You would be better off exporting the data you need and importing them into your new OS/Browser. This also makes sure you can get saved passwords as these are not something you just copy out using raw file copy.

And finally, som uses (and apps) have a habit of saving files to other places like C:\Photos and C:\Movies but also dim things like C:\IntelDriverUpdate (made up name), that also makes it hard for a tool to find the personal files.