After a year and a half time of interval, Google consider again Mobile-First Indexing Algorithm for sites
As per Official news on crawling and indexing sites for the indexing method, Google considers the sites having AMP code with top ranking other than the sites which are not implemented the AMP code and thus shows the AMP implemented sites top in Google.
Google announcing that after a year and a half of careful experimentation and testing, we’ve started migrating sites that follow the best practices for mobile-first indexing.
To recap, our crawling, indexing, and ranking systems have typically used the desktop version of a page's content, which may cause issues for mobile searchers when that version is vastly different from the mobile version. Mobile-first indexing means that we'll use the mobile version of the page for indexing and ranking, to better help our – primarily mobile – users find what they're looking for.