How to find reuse metrics relatively quickly?

I am trying to get counts of conrefs, variables, images and topics included a baseline to present some metrics about the amount of reuse (some factors are ignored). My approach is to parse the fields:

FISHVARINUSE
FISHLINKS
FISHFRAGMENTLINKS
FISHIMAGELINKS

For each baseline, I get the logical id and version of each map or topic. The DocumentObj.RetrieveLanguageMetadata endpoint only allows you to specify 1 version. So, I make multiple calls per baseline for each version included in the baseline. This is very slow since I have to do this for thousands of baselines.

Do you know of a faster way to gather this information?