Please see the demo file demonstrating how to assign uniform value to records that contain variation of the same name, or perhaps are a related group of records.
2 fields are corrected ([Provider LName] and [Address]), using two mapping lists with unique values, and Merge operation with multiple merge criteria, ensuring correct association is made, therefore avoiding many:many matches or incorrect association.

Following formula in the FieldOrganiser helps populate empty fields with the single value, for the given combination of 3 fields, where field [Provider Tax ID] is only partially populated.
SUBSET_FIRSTNONNULL([Provider Tax ID],
SUBSET3([Provider Fname], [LnameCorrected], [AddressCorrected]))