With the change where the top stories carousel with the product experience update in Google Search no longer will need AMP, you do need to meet some guidelines to be included but you do not need to be faster than your competition to show up in the top stories carousel.
Lily Ray said on Twitter "Dropping the AMP icon & opening Top Stories eligibility to all publishers is a big deal. But I assume this is the area where CWV will play the strongest role. I wonder if non-AMP publishers will truly be able to compete with the speed of AMP pages."
The truth is, Google said core web vitals do not need to be met for top stories and John Mueller aded on Twitter "You don't need to be fastest, you just need to be fast enough. (Thinking about lcp in particular - the other things are similar)."
That line says a ton:
(1) You do not need to be the fastest, faster sites won't outrank you if your content is better.
(2) You just need to be fast enough, so that you are eligible to show in the top stories carousel.
John specifically said think "about LCP in particular." LCP is Largest Contentful Paint, it is a "user-centric metric for measuring perceived load speed because it marks the point in the page load timeline when the page's main content has likely loaded—a fast LCP helps reassure the user that the page is useful."
Here are those tweets:
You don't need to be fastest, you just need to be fast enough. (Thinking about lcp in particular - the other things are similar)
— 🍌 John 🍌 (@JohnMu) April 19, 2021
Forum discussion at Twitter.