Do I loose historical data when I replace the 'History Source' aspect from the root to the Control Network object
I can not tell what happens if you below an existing and by some Basic History service group "in use" History Source aspect create a new (and temporarily to a void group pointing) one? The closest to the Log Configuration aspect will be in effect.
Until you have exercised what you plan to do in some "sandbox system" (eg a replica) I strongly advise to have affected Basic History service groups temporarily disabled.
It is indeed possible to accidentally wipe all log content by manipulating the History Source(s).
As I wrote on another thread last evening, Basic History "accept" file manipulation if properly made (service stopped). You can backup/restore with regular file copying (or rather some file compression tool). Broken log<>file references (if new log configurations have been created) can often be repaired with the AdvHtArchive.exe tool.
Murphy1: "Backup often, backup early!"