If you just want a LIST of files instead of the file content itself, you should consider to use S3 API of HCP, as it supports
GET BUCKET V2 (= List all Objects of a bucket/namespace). You could arrange/write a directory structure in a bucket using / Prefix....
But if you want to really access/get/download a file, every GET call is one single operation, even in S3 protocoll.
No, MQE API cannot reduce http calls.
BR
Dirk