If you use netlink operations directly, you can have the kernel filter
on various criteria and only get the socket entries you are interested in.

I suggest to take another look at software design options.

This whole discussion has zero to do with what text format 'ss' outputs.

Is there a need to improve the software documentation any further?

Which programming interface should be used to check the receive queue
for a single port (without retrieving more network data before)?

Regards,
Markus