I'm dealing with a right pain at the moment - Japanese keyword spam has sneaked into my site's indexed pages. three spam titles are still showing up in Google's index, even after I've cleaned everything thoroughly and resubmitted the sitemap a couple of days ago. The pages just won't drop out.
If you're in the same boat, check your pages via Search Console's URL inspection tool. Chances are the spam is hidden in JavaScript that the crawler is still picking up. Worth a look before you pull your hair out.