Hello,
I would like to know if it is possible to hide users from each other (For example, if I am on X’s profile, I do not see who the other users are. Same for Y’s profile).
If this is not possible, is there a way to remove the “contacts” (top left) and “search” tab so that you cannot find other users?
Yes, you can hide a few things via the admin menu. Go to the sharing settings, then you can restrict that user can only do shares with users in their own group, or also disable the auto-completion.
There were some issues, e.g. if you wanted that user can share with each other but so that they cannot see each other mail addresses, which is not possible like this.