When Google indexes and ranks a website several factors are in play, simultaneously.
The SERP (search engine results page) URL order is the result of a process triggered by a keyword search by the user. That process consists in sorting tons of data from several sources, old and new, with almost random variability, summarized with some SEO expert empirical data and politically correct information from Google.
One of those ranking factors is the load speed. Since the process is done simultaneously the speed is potentially the ranking factor your website needs to beat your competitor in the SERP.
The Landing Page Speed Test is an online test that checks and audit a web page in order to improve the loading speed and other parameters.
Most page speed tests used in 2022 are the Google Page Speed Insights tool and the Lighthouse Speed Test. The first is an online tool to check speed website, and give insights about the website performance. The second is a website speed test chrome extension that audit 4 main parameters: Performance, Accessibility, Best Practices and SEO.
Page Speed Insights tool uses real data from users and Lighthouse Page Speed Test use lab data. However both are great for landing page speed test.
According to status (Poor, Needs Improvement, Good), metric type (CLS, FID, LCP), and URL group, the Core Web Vitals report displays URL performance (groups of similar web pages).
Cumulative Layout Shift. Every unexpected layout change that takes place during the whole lifecycle of the page is measured by CLS by adding together all of the individual layout shift scores.
First Input Delay. The period of time between when a user interacts with your website for the first time (by clicking a link or tapping a button, for example) and when the browser reacts to that interaction.
Largest Contentful Paint. The time it takes after the user requests the URL for the biggest content element to render and become visible in the viewport.
Video from Google Search Central
Google says in 2022 that speed is not the most important ranking factor, at the same time insists that the user experience or UX and the relevant content are.
Faster websites give an edge against competitors. Cloud Hosting, perfect website structure, premium plugins, and design oriented towards web optimization are what you need to focus on when looking for the best website or ecommerce designer.