@rreitsema I believe you are asking for this general info : Microsoft's Responsibilities for Apps on Business Central online - Business Central | Microsoft Docs.
However, from what i know personally is that every region has a failover DC(datacenter) whereas in case of such, the failover will occur automatically. Usually there will be a notification distributed to each affected customer (tenant) in the Service Health in Office 365 with the impacted services for a single customer.
For Business Center the MS Support would be the best to be asked.
Backups should be taken automatically at least once per day and approximately 2 years ago, each SaaS service provided by MS , should have the Point-in-time restore point, besides the daily occurring one. In case of urgency , such PIT(Point-in-time) restore can be requested via the MS Support.
Regarding the encryptions , this is a much greater topic and I do not feel I can answer it.
Anyways, the MS documentation , and especially the MS Learn would give you more information. If you feel i can be at help specifically for CRM - let me know.
