Does it make sense to use AWS Microsot Managed AD for use it as a Secondary Domain Controller of an on-premise controller?

This may be useful if you are migrating from on-premise.
https://docs.aws.amazon.com/directoryservice/latest/admin-guide/usecase5.html

You cannot add an AWS-managed AD domain controller to your on-premises AD domain. However, assuming all network connectivity and routing configuration is in place, you can deploy an AWS EC2 instance as a second domain controller but you should assess the network connectivity resilience, latency and bandwidth between your on-prem AD domain controller and AWS. If your on-prem domain controller is off-line, consider the impact of losing your connection to AWS. Do you have redundant links out of your DC and into AWS to protect from link failure? Will there be increased network latency between the AWS-hosted domain controller and your users/application servers? How will this impact application performance? What network capacity does your link to AWS have and how much is it utilized normally? What additional network traffic will be carried on this link during an on-prem domain controller outage? How will this impact application performance?

AWS Launch Wizard for Active Directory is a service that applies AWS cloud application best practices to guide you through adding domain controllers to an existing infrastructure on premises, so would probably be a good place to start. https://docs.aws.amazon.com/launchwizard/latest/userguide/what-is-launch-wizard-active-directory.html