If your save game data ever gets lost or corrupted due to the server crashing, you can restore your data from the automated server backups.
The autmoated backups only run every 2 hours if the server is online. If the server is scheduled to be stopped, or has crashed, it will not create a backup slot.
If you do not currently see any backup data in the nitro panel, you can manually create a backup file. More info on how to do that can be found here:
How to Create Backups
Do not Delete all files before restoring backup. Backup files only contain config and save files