How to extract a json / xml with the requirements of a project in DNG?

At my company we are developing some extensions in DOORS Next Generation for a set of projects, and we would like to know how to extract the requirements so we can create different charts and graphics based on the value of their attributes (id, status, etc..). We are hosting the extensions into an Azure server, so that it reads the ".xml" of each of extension and runs the corresponding ".js" files when it loads on the DNG widget.

Currently we are working with the Reportable API, but it is messy and slow whenever it loads the extension - this way extracts all the data from a given project and later we need to apply various filters to retrieve the useful data. Our problem is that we need to particularize this for every project, as each database may contain different attributes for each artifact.

We have looked deeply into the documentation and it seems to be a way of working with "RM" calls, but we have not found a solution to make that the extension recognizes the "RM.data." instructions, like the ones shown at the code of the example available at the following link (https://jazz.net/wiki/bin/view/Main/RMExtensionsSimpleExamples702).

We have also considered to retrieve data using OSLC queries as in this video (https://www.youtube.com/watch?v=YzrVo6YM0iQ) but we still need to apply various filters to retrieve data, and therefore difficult to handle with.

Is there any other solution that would retrieve the data (for example, via SQL query) with the required filters of the attributes already applied? We have also looked at the json format link available when accessing at the Report Builder (which is designed to be coupled to IBM Engineering Lifecyle Optimization - Publisher), but the problem is that it does not update the register/report if new artifacts are created inside the requirements module.

All answers or past experiences related to this topic would be of much help. Thanks in advance.

Pablo