In AWS I would use an RDS service to prevent spending much time on database management. You can point your App to that database. Goto your App settings → Configurations click <New>.
I’m curious what is the reason to have the middleware in a private cloud and the data in a public cloud. In most architectures I have seen, the private cloud requirements are driven by the wish to have the data locally stored.
If connectivity, consider the use of a reverse proxy and a load balancer for HA.
You will need a license and the software from here:
Managed OS and Managed RDBMS costs are very much dependent on the SLA/Service window etcetera. I can share you some details in a mail.
Yes if you can share with me could be great. my email: firstname.lastname@example.org
The requirement its because the client want to have their database in their own private cloud in AWS account instead of mendix private cloud because less costs of storage.