There may be some holes in this post but something is better than nothing
Following this guide should cover you in any unforeseen event, a compromised server for example. The procedures are very easy and can be performed in less than an hour. As the procedures followed carefully won't do any harm, it's a good idea to perform them and then spend a bit more time learning the details about restoring your site afterward. #^Quickly Backup a Fediverse Instance: no excuses
Here's an attempt to collect the essential commands backing up instances of various types. Following this guide should cover you in ...