Hello, I am new to SEO and I've got some doubts about how the crawlers work. I tried to look up for info but I couldn't find an answer to this specific question. As for my understanding, page speed is important to Google in order to index pages, and core web vitals like First Contentful Page (FCP) are important for a good ranking.

I know as well that server response affects the FCP performance.

If I want to serve an audience in two specific countries and my traffic comes predominantly from these two countries, in order to speed up the server response, how should I choose the server location? How does Google detect the page speed? Is that via crawlers? When Google crawlers analysise web pages, where do "they come from?". If Google sends its crawlers from the US, as an example, and my server is in the UK, it'd detect a slower server response.

Please, if anyone can help clarify.

Thanks