Dataverse Lookup Backfill & Guidance

I’m in the middle of building a Microsoft Power Apps solution on Dataverse and Power Automate. Right now the priority is a backfill: I need to convert several imported text fields into proper Dataverse... (Budget: $8 - $15 USD, Jobs: Data Analysis, Data Integration, Data Modeling, Database Management, Power Automate, Software Development, Technical Documentation, Troubleshooting)