Hi @JakeW ,
Please make sure you're using this guide https://help.shopify.com/en/manual/products/import-export/import-products
Also this may be a setting you would want during an update import.
Click the Replace any current products that have the same handle checkbox.
I ended up deleting some unnecessary fields, although I can't remember which. Whenever I am doing a batch update I now use the same format/fields to upload, which includes these fields:
|handle||sku||Title||Body (HTML)||type||Option1 Name||Option1 Value||Option2 Name||Option2 Value||Option3 Name||Option3 Value||Variant Grams||Vendor||tags||variant price|