Do you have web disk or ssh access? If so, and you have daily or weekly backups enabled in cPanel you can just grab backups of the server and database from the standard backup locations if so. Or, do you have backups enabled to a remote location? If your only admin access is through Xenforo itself, you could install an add-on that provides it's own backup mechanism e.g.:
https://xenforo.com/community/resources/solidmean-forumbackup.3605/
Note: this only copies the backup locally. They have another add-on to SFTP the backup to another host:
[SolidMean] ForumBackup SFTP Transfer