If you do use timeshift or btrfs & snapper or any backup-program, you can get them back.
You find good Information about Btrfs in the wiki
and in
https://forum.manjaro.org/t/how-to-manual-rollback-with-btrfs/80230/5
https://forum.manjaro.org/t/how-to-rescue-data-from-a-damaged-btrfs-volume/79414/4
Make Backups: