FID is directly related to real user interaction, so it cannot be simulated in an artificial environment. There are special JavaScript libraries for measuring FID, but to understand the situation it is better to use real user monitoring (RUM) tools. Google itself checks sites from the point of view of average devices and not the best Internet connection - to cover different users.
The first-input latency estimate for the same page will vary from case to case, as it all russia rcs data depends on the specific device on which the page is opened and the specific actions of the user, who may click on interactive or non-interactive elements with unpredictable frequency.
One of the best sources of data for evaluating Core Web Vitals is the Chrome User Experience report .
It collects data from real users (who have synced their search history across devices and agreed to collect statistics) over the past 28 days. User statistics from the Chrome User Experience report are available in various Google services: PageSpeed Insights, Search Console, Data Studio.
SE Ranking also incorporates Chrome User Experience data. In addition to reviewing the data, you can go to the errors section of the report and see a more detailed analysis of Core Web Vitals.