When an order has several items, its order ID appears on several rows. To compare two exports, match each row on both order ID and line number. This still works if the rows were sorted differently.
For example, order 001, line 2 goes from quantity 4 to 6. Order 002 disappears, and order 003 is added. Those are three separate changes. A new warehouse column is a header change, so review it separately from changes to existing values.
Before comparing, check that each pair of key values occurs once per file. Preserve leading zeros and export both files as UTF-8 comma-separated CSV. If the same key appears twice, resolve it before relying on the results.
CSV Change Audit includes two sample exports that reproduce this example. It runs offline in a desktop browser and exports a JSON change report. The download is $12 once.