Hello,
I believe that this is currently not possible (unless someone else corrects me that I'm wrong ). The reverse is possible, to not filter on the details by adding the extended property DisableFilterOnDetails to your runtime configuration. However, no such setting exists to disable filtering on the main subject and solely focus on detail subjects.
One workaround could be to limit the amount of columns that have to be searched in the main subject as small as possible, if you mostly search on the details anyway.
If you really wish for such a setting to be implemented in the future, you can consider creating an Idea for it in the Ideas section of the community: https://community.thinkwisesoftware.com/ideas
Kind regards,
Renée