In Google Search Console, you can add and remove sitemaps from your site, and Google will include information related to the sitemap files such as any warnings or errors, as well as pages indexed from the crawl.   While Google can discover and crawl sitemaps on its own, submitting makes it faster and easier, and it helps for tracking indexing.  You can also remove a sitemap from Search Console as well.

But removing a sitemap from a site within Google Search Console is not a viable solution for stopping Google from crawling a sitemap file.  It will stop the errors and warnings that show up related to specific sitemaps in Search Console but Google can still crawl and attempt to index links within those removed sitemaps.

If you no longer want Google to process a sitemap file, you also need to remove it from the server itself.  If you can’t remove it, renaming the file will work, unless that new file is linked to from somewhere, in which case Google may still try and crawl and process the file.  And because it was removed in Search Console, you won’t get any of the errors or warnings associated with it, even if Google continues to process it.

Usually what I’d recommend doing there if you submitted a sitemap file that has a lot of errors in it then I would either try to fix the sitemap file so there’s actually a more valid sitemap file or at least remove the sitemap file from the server.  So as long as the sitemap file is still on your server and it’s just not listed in search console, we could still crawl that and try to process that sitemap file.

So if you really want that taken out, I’d recommend removing it from your server directly or fixing your sitemap file in Search Console.

So if you are trying to figure out why Google is still crawling based on a sitemap you have removed from Search Console, you need to still remove it from the server, because Google still knows it is there and could be using it.