Adding to what Antonio mentioned, there are other maintenance tasks such as Audit log purge, .. etc. They are listed in the earlier update I made.

You can exclude specific contents form indexing:How to exclude certain paths of content from being indexed

Please check this thread:AEM - Ways to reduce repository size

The recommended upgrade method is in-place upgrade that is supported for moving from AEM 6.0 to AEM 6.3 directly. Please pay close attention to content repository migration to ensure you use the right command for this purpose. You may want to review the following document:Performing an In-Place Upgr...

Ref: did all of the /etc restructuring happen in 6.4? If the 6.5 doc does not list anything additional to what was announced for 6.4 then that is it.Ref: Are there 6.4 features that use etc that are no longer supported in 6.5Deprecated and Removed Features

You may wanna ensure you have the proper user permissions to perform this task. http://host:port/useradmin

The package may include thousands of nodes that can potentially create memory issues.- Do you see any relevant error message in the "error.log" file ? Any Out Of Memory error ?- If so can you increase the allocated heap to AEM by using the proper size in the startup command ?Example: java -jar -Xmx8...

I verified the following packages are created in CRX/DE upon uploading the package:/etc/designs/mfCoral63/apps/mfCoral63/content/mfCoral63/content/dam/mfCoral63- What version of AEM are you running ?- Do you see any error in the "error.log" related to uploading the package ?

Please note that support for PostgreSQL is provided only for demo purposes. It will not be available for production environments. you may want to use one of the RDBMS that is officially supported:RDBMS Support in AEM 6.4

The JCR Query Cheat Sheet can help you. It includes useful samples: https://wiki.magnolia-cms.com/display/WIKI/JCR+Query+Cheat+Sheet