When we block CSS files on the CDN through robots.txt, the report on mobile-friendliness in GSC is red, would this affect the actual ranking?
Yes, it can cause issues and you should avoid doing that. Being able to see a page completely helps us to understand the page and confirm that’s mobile-friendly.
If there is simple guide sitemaps available?
Unfortunately there is no solution that works across all kinds of websites. However, most website setups have simple sitemap solutions of their own. Check your site’s documentation for a sitemap setting or for a plugin that creates sitemap files. often, It’s just a matter of turning that on and you are all set.
It is possible to reset the indexing of a website?
Unfortunately no it’s not possible to reset indexing. However, the good news is that if you have changed your website, search engines will automatically focus on the new version and drop the old version over time. You can help this along by redirecting from any old URLs to the new ones.
Is having RSS feed is problematic for crawling, since googlebot fetches so foten?
No, these are not problematic. Google system balances crawling across a website automatically. Sometimes this means crawling some pages more often but this only happens once we have looked at important ones.