ShipScript has been an eBay Community volunteer since 2003, specializing in HTML, CSS, Scripts, Photos, Active Content, Technical Solutions, and online Seller Tools.
Yes, bulk uploads are possible with Seller Hub > Reports > Uploads:
https://www.ebay.com/sh/reports/uploads
On that page, download a template for each of the major categories that you will need for your items. Select the XLSX option, as that file contains all of the options you would normally encounter on the listing tool.
As you populate the spreadsheet from left to right, your selections will determine which cells become mandatory, and your options for those cells may change based on an earlier selection. Droplists may appear within each cell to be populated.
All data can be uploaded this way, although the photos may be a problem. The spreadsheet will only accept URLs for online photos. If you don't have an online server for those photos, you would have to manually add photos to your listings after the uploads. In that case, you may need to put dummy URLs into the spreadsheet and delete/replace with a manual edit to the listing.
Also look at the left column of the Uploads page and take advantage of "Learning Resources".
