You sure can use the Matrixify app to bulk update inventory by importing only adjustments and using SKU as identification.
You can import a file with only two columns using the Matrixify app:
- Variant SKU
- Variant Inventory Adjust (if item is stocked in multiple locations then you will need to specify the location and thus use column header
[Inventory Available Adjust: Location Name](https://matrixify.app/documentation/products/#inventory-available-adjust)(change the location name to name of your location))
If you have any questions or concerns along the way, feel free to contact Matrixify support directly.