What do 'Archive' and 'Hide Model' do?
Archive means the page remains available but the model cannot be downloaded; it is intended to keep explanations, prompts, reviews etc up. (See https://civitai.com/questions/1352/why-cant-i-download-the-model-after-archiving or look up the changelog on discord circa april.) That's kinda the opposite of what you want.
Unpublish means inaccessible to anyone but the author, so that's not what you want either. Usually see it in the context of inappropriate content.
Hide model, I only know that feature in the context of the user - it does pretty much exactly what you want, hides or dims the model on the front page / search / user page, but leaves it accessible via url. However, I am not aware of such a setting on the author level, and it's kinda weird you can do that to your own model.
Honestly, if you're looking for a place to dump models anonymously, civitai is hardly the place for it, as it's based around open sharing. There's a ton of solutions for protected file sharing already. And if it's for a collab, perhaps batchlinks extension can be of use?