Axel,
Did you see the cusomization section here as well this sems to allow for customizing what is send to datadog:
https://docs.mendix.com/developerportal/operate/datadog-metrics#customizing
But not sure on what additional options there are and what the connector is that is being spoken of in the blog.
Maybe try to contact Andrej Koelewijn via slack as he is the author of the blog.
Found it!
https://github.com/ako/MxAppMetrics-main