If you don't care about metadata, why do you want to use Zotero? If you don't need metadata/citations, it'd sound like Obsidian would be sufficient and you don't need to deal with Zotero or what are you after?

But generally you can click on File --> Add Attachment --> Add link to file and then bulk select all PDFs you want to add.

With 1000 PDFs, it would be best to first add a small chunk (say 10), to see what they look like in Zotero.

Using the File\Add Attachment\Add Link to File method, they will come in as standalone "linked" PDFs. Most "items" in Zotero instead usually consistent of a parent (which includes all the information *about* the PDF - its title, author, date, etc etc ... that's what metadata is) and its PDF attachment. Leaving PDFs as standalone does limit some of the things you can do with them ... but as you didn't say what you want to do with them, it's unclear how limiting that would be for you.
https://www.zotero.org/support/adding_items_to_zotero#standalone_attachments_and_parent_items

As noted, as you wish to keep your PDFs where they are in your OS you would be adding them as "linked" attachment files (Zotero's usual way of adding PDFs is as "stored" files, which are copied to an arbitrarily-named folder under Zotero\data). You can also add linked files by dragging them into Zotero (with modifier key to make them linked rather than stored - see details at URL below). Zotero will then *also* try to extract/find metadata and create the parent item for you (that usually works well for things like journal article PDFs ... but if your PDFs come from more obscure sources, Zotero may not be able to find any metadata). Again, you should just drag a small chunk of PDF files in as linked files, to see how those look.
https://www.zotero.org/support/attaching_files#adding_linked_files