If even file owner is not preserved (it is not always root, espetially in /var), you likely lost files’ extanded attributes an, maybe, also permissions. Without them your system won’t work normally.
Then, contents of these directories must be consistent with other ones. E. g. /var contains a package manager data about packages you installed. If you installed/removed anything after creating a backup, information about this will be lost.
If you created the backup while system was working, some files (espetially under /var, again) could be changed during that process, and this also makes such backup unusable. Every sysadmin knows that to create a database backup by copying files, dbms must be stopped.
In future, think about restoration before planning a backup and test if this possible immediately after it is done.