XML Sitemaps give hints the search engines that, What's the content about so in this sense you have to very much attentive to generate your XML sitemaps or RSS/Atom Sitemap (/sitemap.xml and /feeds/posts/default?alt=rss) and on Sitemaps submission on Google Search Console (choose your property and step forward to submit sitemaps) but care about for generating XML Sitemap cause Robots Blocked Text URLs aren't functional in XML Sitemaps and Consider Canonical URL Following To Build XML Sitemaps.
Sitemap: XML/RSS/Atom/?
If you are a non-technical SEO professional then RSS/Atom feeds suitable for you and you are Technical SEO Professional then XML formatted Sitemaps for you cause:
* RSS/Atom sitemaps are automated so there isn't something special to more attention on it.
* XML Sitemaps are not automated also needs technical knowledge to build and handle it, I.E. your site obtained 100 blog post and have 10 pages but after publishing your XML sitemap, you are seeing that search console discovered 100 (-/+) URLs but not all of your site URLs just because of a few of dead and bad links (use chrome extension, search console, SEO tools and Software to find out the dead links and bad links) and not publishing website/blog page as a separate blog post or web post (see the latest captioned image) by that means you need to create a new link for your each of blog/web page as a regular post to hints the Googlebot that there have a something to Crawl and Index.
"Create a new link for your each of blog/web page as a regular post (specially for XML Sitemaps) to hints the Googlebot that there have a something to Crawl and Index". - Momenul Ahmad
What's the ultimate guide to generating the ultimate XML sitemap and what should follow for?
When you are generating XML Sitemap, not HTML SItemap then follow the below SEO Optimize Nine "9" XML SItemap building steps and the ultimate guide of the ultimate XML Sitemap that will help you to skyrocket your technical SEO also will give the best hints to search engines to crawl and index your content very easily:
SO, When you are preparing to develop or building a sitemap structure whether it's XML, RSS/ATOM or HTML sitemap then must follow this Quality Guidelines of an ideal Sitemap and this must have quality guides of XML Sitemap also should be obtained in all kinds of Sitemaps.
Quality Guidelines To Follow In All Sitemaps:
1. All XML sitemap should be accessible.
2. All XML sitemap has to be the valid structured.
3. XML sitemap should be present.
4. All XML sitemap should be within the file size limit.
5. All XML sitemaps are within URL count limit (no more than 50,000 URLs).
6. Readable XML sitemap should be present.
7. All XML sitemap should be discoverable.
Read more on SEOsiri, The ultimate guide to Sitemap