Bareos (Backup Archiving Recovery Open Sourced) is a reliable, cross-network Open Source Software for backup, archiving and recovery of data across all common operating systems (Linux, UN*X, MacOS, Windows).
Bareos offers its own web frontend as well as integration into the Univention Management Console. With Bareos file or rather directory trees can be configured centrally and then automatically and periodically be saved as a full, differential or incremental backup onto hard drives, tape drives or into the cloud.
Via a web frontend administrators or users can select files for recovery. Due to open interfaces Bareos can easily be extended with scripts or plugins, e.g. to run application-specific commands before, during or after a backup.
Plugins for backing up MySQL/MariaDB, LDAP, MSSQL or VMWare Snapshots incrementally are already available. If you want to play it safe, you can optionally rely onto the subscription- and support-offers of the manufacturer.
The Univention blog contains a series of articles about installing Bareos and backing up additional clients: https://www.univention.com/blog-en/2019/02/linux-and-windows-backups-bareos-in-the-univention-app-center/. If you are using NextCloud and want to backup it's data: here is a dedicated blog article to achieve this with Bareos: https://nextcloud.com/blog/how-to-back-up-nextcloud-with-bareos/