It may be possible to create a UI using a monitoring program like Zabbix.
You could create a custom dashboard that displays all the stats that they need to see.
This of course would be for viewing only, not controlling the schedules, retention etc
Markor on Android and Obsidian on Desktop.
All synced with syncthing
Look at Mikrotik. Very affordable and extremely powerful. Only do this though if you know what you are doing with networking
NPM is great! I even use it in a production environment at work for a small service and it works beautifully
I have a borg server in the office that takes backups of all my servers. Each server stores their applications backup that gets pulled into the repo. On top of that, the borg server pushes the backup to rsync.net.
All of this is monitored by my Zabbix server
Debian