Does AWS RDS Multi AZ in conjuction with read replicas have less replication lag than just read replicas?

Question

Quoting the AWS docs:

"You can use Multi-AZ deployments and Read Replicas in conjunction to enjoy the complementary benefits of each. You can simply specify that a given Multi-AZ deployment is the source DB Instance for your Read Replicas."

Does a Multi-AZ read replica have less replication lag than ordinary read replicas? I ask because for Multi-AZ it states: "it synchronously replicates the data".

Also:

"Multi-AZ deployments utilize synchronous replication, making database writes concurrently on both the primary and standby so that the standby will be up-to-date in the event a failover occurs. While our technological implementation for Multi-AZ DB Instances maximizes data durability in failure scenarios, it precludes the standby from being accessed directly or used for read operations. The fault tolerance offered by Multi-AZ deployments make them a natural fit for production environments; to learn more about Multi-AZ deployments, please visit this FAQ section."

Answer 1

Multi-AZ RDS establishes a Secondary replica of the DB in a different AZ and is replicated synchronously. It can only be accessed when promoted to being the Master DB instance and is used exclusively for disaster recovery.

Read Replicas are an asynchronous replication of the Master DB instance and can be created in one or more AZs/Regions.

The two features operate independently of each other. Secondary RDS instances are not used as a source for RR's therefore any RR lag will be constant regardless of the RDS availability configuration.