A noindex robots meta tag is added to the sitemap on purpose. This is in line with Google’s guidelines and that is how sitemaps work.
Please submit your sitemap_index.xml file to Google Search Console so Google can see all URLs in your sitemap.
Please note that it is completely normal for a newly published post/page/website to take time before it gets crawled or indexed by Google. It depends on a lot of factors. Your posting frequency + the domain authority are just two of the many factors Google considers when indexing some new URL. Google assigns a crawl budget to your website depending on these factors (especially these two) and that has a direct effect on how soon or how late your content can get indexed.