Thanks for your help Christophe.
That note does introduce changes but not to the method at fault in my scenario.
I have logged a message with SAP support.
With the help of DBAs we identified for example that instead of accessing the view, the query should instead go to the tables (CRMD_PARTNER and CRMD_LINK). With the indexes on those tables, it will give much better results.
I will give feedback when we sort this out.
Regards,
Helder