page speed = serp?

What's your page speed versus your serps?

What position is your site and how fast does it load?

https://gtmetrix.com/ <--- to test speed

Anyone over 2 seconds ranking top 3?

https://searchengineland.com/google-speed-update-page-speed-will-become-ranking-factor-mobile-search-289904

you cant make a general comment that anything with a X second will rank in top 3. it depends on whole bunch of variables, and speed is one of them. you could have the best page speed, but if your onpage seo sucks and your backlinks sucks, you won't get ranked.

i suggest to also look at https://www.webpagetest.org and in particular the "first byte time". try to get all A scores using this tool. except the CDN part.

as for GT metrix, try to get all A's on page speed tab.

Page speed is just a factor for ranking

serp is the ranking on the search engine