Excel Merge with updates using power Query

Hello all!

I'm a new member, I can't wait to meet and start to contribute to this Forum.

I have a questions regarding the best way to manage a workbook. Everyweek I export a excel sheet from a proprietary system. This exported sheet has all the updated information that I would like to see.

Everyweek when I export this sheet I go over the data with my team, I add columns and data validations in order to dispatch certain tasks team members need to take (Email a team/close an engagement). However in the current state this is being done and replicated everyweek.

I want to create a system where I have one master data set and once a new week passes new data can be merged to update/add/delete records.
I have looked into Powerquerys and the trouble I'm finding is that how can I tell the system to transpose the new data and keep the added columns I have already created.