How to revert history?

One of my users made quite a mess.

He has two computers, one used every day and synchronized to nextcloud, the other one he turns on every 3 months. When this second computer synchronizes with the cloud, it sends back old files as if they were recent changes. So all the folders end up with old files/folders, it’s a huge mess.

Is there any way to say that all changes should be undone? All those made by a user over a certain period of time. Here, everything that was “synchronized” on Sunday should be undone.

Unfortunately, that’s impossible because such a function doesn’t exist yet.