Google's ranking factors include Core Web Vitals - a set of metrics for evaluating loading stages. For example, the search engine analyses the website's loading speed and rendering time of the largest element, the speed of response to the first user action, and page layout shifts.
You can check the Core Web Vitals using this tool, which will show data from Chrome's page-list report. The report includes aggregated data from real user interactions.
It includes three metrics: LCP reports the render time of the largest visible object within the viewport, FID indicates the responsiveness of the website to the first user action after loading, and CLS is a measure of how much a webpage layout shifts during the element loading at the top of the webpage.
The tool pulls information from a Chrome report via Google API. Chrome aggregates data about user interactions with the webpage. If users did not visit the webpage through Chrome, the system has no data, and our Core Web Vitals metrics tool cannot report anything.
Google has thresholds for each LCP, FID, and CLS metric. The Core Web Vitals check is considered passed if a webpage has sufficient data for these thresholds. The tool will display this in green. Keep in mind that any improvements greater than the threshold do not affect ranking, so it's useless to perform any micro-optimization.