Hello,
There are lots of tools here for Office 365 Backup like Veeam, Spanning, Sky kick, Datto, Code two but I personally recommend you to go with AvePoint. AvePoint is the best option. It is a fully managed cloud-to-cloud Office 365 backup with the storage and management panel hosted by AvePoint. AvePoint O365 backup, where you need to log in separately to manage backups and recovery. It also supports customer-managed encryption key and enables backup of Office 365 applications that few other vendors support, such as Dynamics 365, MS Project Online, and Yammer.
I hope this information helps you.