The easiest way to go about this would be to talk to your Account Executive so he/she can provide a license key for your AWS environment that uses some of the licenses that you have still available. Each environment would be separate and therefore each one would have its own QMC.
for my personal experience, you need 2 licenses (split your current license or purchase a new one for AWS).
Duplicating the environment is not a good solution because you will have 2 qmc, 2 systems to maintain and if you split the license you can lose some efficiency in the Access Logins Tokens.
I believe also there is a hybrid solution base on a Qlik Sense cluster partially on Premises and partially on AWS, but it sound to me as a complicated solution, and I never had the courage to try.
I finally chose to move everything on AWS (Redshift, S3, EC2). I cut my cost of 60% and got more speed and reliability. My AWS big data specialist show me also the new generation services that will improve drastically the performance and reduce the cost: Athena (Serverless queries on S3 to load the data without using Redshift) and Glue (new AWS integrated ETL tool).