Not sure is you’ve seen this documentation, but you can get discrepancy check using table compare
https://docs.perspectium.com/display/fluorineplus/Table+Compare
And if checking between servicenow instances (InstanceSync), you can also generate a list of sys_id’s missing locally and automatically create a bulk share for it https://wiki.perspectium.com/doku.php?id=replicator_table_compare
David