For years, I thought the only way to submit a sitemap was just using Google Search Console and hoping that they crawl. This articles from SE Round Table links to some tweets and some documentation that you can send a get request to Google to let them know a sitemap has been changed. I am not sure that it works and will be trying it. But, another thing for the toolbox for sure.

https://www.seroundtable.com/pinging-xml-sitemaps-google-34236.html