I agree, that a restore of the last backup ist the preferred solution. But you loose all syncs between the time of backup and the restore. On a system with many users this can result in data loss.
A file by file restore of the last version of the infected files can prevent that. Nextcloud has the possibilities to do that. What is missing is the bulk operation. For example with restoring files from a specific user beginning with the time stamp of the first sync of the damaged files.
file by file restore doesn’t work in corporate networks. To give you some numbers: Daily amount of altered files from one customer (200 users) is approxx 10.000 files. Nextcloud is not the right tool for this mission. If there’s no WebDAV or SMB access (via external data storages) then Nextcloud is great when User and File Seperation counts. The Web Interface is kind of barrier for all file-based tools and in combination with OnlyOffice Users can work seamlessly. In combination with RDP2HTML (running within Nextcloud as External App) this is a perfect solution for all mobile information workers.
https://cloud.jakobssystems.de/s/sNbsLVFkDl90cJw/download
P.S. how to embed pictures from your own Server here?
. In combination with RDP2HTML (running within Nextcloud as External App)
Which one is the best to use alongside Nextcloud?