Possible to compare data from two files and merge/format that data into an output table where additional columns can be made/filled and that data survive the next import?

Sorry for the verbose subject but trying to be descriptive. In this case we have an asset management system that allows our property book officer to track basic equipment details like serial number, barcode, etc. We get exports in CSV format for our current equipment list periodically. What I want to do is query the folder and take the latest two exports and then merge that data and do comparisons on the fields to see which have changed and then do data formatting to highlight the changes since our last export to tell us what we need to focus on verifying (specifically what has been added or removed).

All of that I'm very confident I can do. What I'm not as confident of is what else I'm looking to do. In the sheet where this is output I want to add additional columns for details that aren't tracked in the asset system (POC, Bldg/Room, EOL date, Notes) and the next time I drop a new export and run the import have it retain the additional notes I made in the columns for any items still present on my current asset list.

Please note we work in an area where VBA and macros are not allowed so this all has the be doable within Power Query and/or internal Excel formatting.

Is this possible?