In an AskGooglebot session, one SEO professional asked John Mueller about removing sitemaps in Google Search Console.
John demonstrated a simple method for removing any sitemaps from Google Search Console.
Once you remove it, Google will stop tracking the sitemap within Google Search Console.
Alternatively, it’s possible to remove your sitemap file so that it returns a 404 or 410 HTTP status code instead, which means that the file just isn’t available for crawling.
Google will end up not using these deleted sitemap files to crawl your site over time.