The following databases are available in AWS, PostgreSQL, MySQL, MariaDB, Oracle, MS-SQL Server amd Amazon's own Aurora

Automated backups are set up by default. They can be configured to be retained from 1-35 days. A full daily snapshot is taken as well as keeping the transaction logs. The backups are stored in S3. You are entitled to free S3 storage up to the same size as your database for this purpose.

Snapshots can also be taken but these are user initiated.

Encryption at rest is supported for all the non-AWS database backups.

Restoring can be from snaphots, which create a new database and can be restored to a point in time. Snapshots can be copied to different regions and then used for a restore there.

Multi-AZ replication uses replication between availability zones. If the primary AZ fails, automatic failover occurs to the standby. This feature is available for all non-AWS DBs.

Read Replica useds async replication to create a read only copy of a DB. This is used for performance improvements rather than DR purposes. You can also create a replica of a read replica. Reas replicas only work with MySQL, MariaDB and PostgreSQL.

To make use of this feature, automatic DB backups must be enabled. Too many replicas could lead to latency. Read replicas cannot be Multi-AZ. Each replica will have it's own DNS endpoint so to make use of a read replica, applications need to be configured to point to it.