If I import a CSV product list into my store and the overwrite option isn't selected will my inventory quantity still update?
I will wish to import frequently in order to ensure quantity levels are up-to-date but I don't want my product descriptions over written with the standard supplier description (as I have edited/personalised these previously)
When you use CSV to import you can first delete the columns you don't want to overwrite and the previous values will remain unchanged.
I suggest you to try with 1 product first to be sure your CSV template is correct and the proceed to update multiple products.
Use the inventory import for this
Single Location - https://help.shopify.com/en/manual/products/inventory/inventory-csv