There are some readily available tools which fasten the process of upgrading older AEM to AEM as a Cloud Service.
Cloud Readiness Analyzer-CRA
--->Cloud Readiness Analyzer report is built using the output of the Adobe Experience Manager (AEM) Pattern Detector)
--->This gives high-level understanding of general upgrade readiness.
--->Helps accelerate the processes of assessing readiness to move from an existing Adobe Experience Manager (AEM) deployment to AEM as a Cloud Service.
--->This tool generates a report that identifies areas of potential refactoring, which is the first step in the transition journey to AEM as a Cloud Service.
--->CRA is supported on AEM instances with version 6.1 and above (CRA is supported on AEM instances with version 6.1 and above)
--->CRA can run on any environment, but it is preferred to have it run on a Stage (Author) environment or clone of the production Author environment
--->CRA can be downloaded as zip and uploaded to AEM instance via Package Manager