I mean also structured data, check the read after, and see what they are talking about. Also, checking on web.dev tool by google, canonical are not valid in a way. 

You can enhance your AMP content for Google Search by creating a basic AMP page, adding structured data, monitoring your pages, and practicing with codelabs.

1. Create your first AMP page.
2. Follow the Google Search guidelines for AMP pages.
3. Make your content discoverable by linking your pages. For crawling and indexing, Google Search requires that an AMP page links to a canonical page. The canonical page can be either a non-AMP version of the page or it can be the AMP page itself. For more information, see the What's in an AMP URL? developer blog post.
4. Ensure that users can experience the same content and complete the same actions on AMP pages as on the corresponding canonical pages, where possible.
5. Use the AMP Test Tool to ensure that your page meets the Google Search requirements for a valid AMP HTML document.
6. Use the same structured data markup across both the canonical and AMP pages.
7. Apply common content best practices:
   1. Make sure that your robots.txt file doesn't block your AMP page. Use the meta robots noindex, block indexing, and robots meta tags.
   2. Follow the guidelines for hreflang for language and regional URLs. For AMP specific examples, see Internationalization.

If you serve your web content through a Content Management System (CMS), you can use an existing CMS plugin (such as for WordPress, Drupal, or Joomla) or implement custom functionality in your CMS to generate AMP content. If you intend to customize your CMS, follow these guidelines in addition to Create a basic AMP page:

• Consider how AMP HTML files will fit your site's URL path scheme. If you’re generating an AMP page in addition to a canonical non-AMP page, we recommend choosing one of the following URL schemes:
  • http://www.example.com/myarticle/amp
  • http://www.example.com/myarticle.amp.html
• Develop a structured data markup template. Here are some guidelines:
  • Construct the template based on the requirements for the type of content you are publishing.
  • Refer to AMP Project metadata examples for sample templates for recipes, articles, videos, and reviews.

Use structured data to enhance the appearance of your page in Google mobile search results. AMP pages with structured data can appear in rich results in mobile search, like the Top stories carousel or host carousel.

1. Implement structured data. For more information about AMP-supported structured data, see About AMP on Google Search.
2. Verify that your structured data parses correctly by using the Structured Data Testing Tool.
3. Ensure that your logo meets the AMP logo guidelines. If your logo is missing or not properly formatted, it will either be displayed poorly or not at all in the Top stories carousel.
4. Verify your complete AMP for Google Search by using the AMP Test Tool.

https://developers.google.com/search/docs/guides/enhance-amp

Also, on amp pages i with to have Schema.Org setted on "NewsArticle" Type, but cannot see any mention on the source code of one of my pages in amp.

https://wordlift.io/blog/en/amp-structured-data/

I've read this document about canonical Amp pages

https://www.ampproject.org/docs/fundamentals/discovery

Unfortunately i cannot see any reference about this when i check content source of any of my pages.

Can you please check it?