RDS for database size more than 16TB

There is a lot of ways to look at the ask, best recommendation is to look at the main SQL page on AWS.

The page has information on Migration methods for SQL and host types you should consider among other things. Additional information on SQL on RHEL as well. Blog on Deploying SQL on Linux on AWS will be another resource to us.

For backups, you can use AWS Backup in a lot of cases to backup EC2 instances. Depends on how you want to backup and how often. You can also export the backups to a AWS storage offering like EFS, FSx, or even S3 depending on the architecture.

RDS running Microsoft SQL is another option to consider.