Check out Index Creation Possibility with Sorted Data based on Some Field - #4 by vsr1
Also, each query is different, no way it guarantee if data is changing with ORDER BY, OFFSET.
See if keyset pagination works for your needs Using OFFSET and Keyset in N1QL | The Couchbase Blog
If request is simple and want speed up. Use covered query and get all the keys. Then use SDK reactive API with multiple threads and fetch the documents.