Which metrics to use to evaluate web hosting performance from all over the world?

Question

I have a website that is hosted in Europe but most of the visitors are coming from the U.S. When testing the website from a quick USA VPN it shown really poor speed load performance: >6 seconds speed load time compared to <2 seconds when accessing it from Europe.

To speed up the web load time from the U.S. I would like to get it on CDN. I would like to monitor the whole process so I can see how exactly that improved.

Which metrics should I follow for that?

Could you please explain why to use which metric and to which put the most weight?

I know there are e.g. First Contentful Paint and Largest Contentful Paint in PageSpeed Insights but that shows the overral page speed load. That changes when I change the website. I want to see the hosting / CDN speed only.

Answer 1

TTFB, Network Latency, HTTP/HTTPS Request Timings, CDN Cache Hit Rate, Geographical Performance Data

Answer 2

Which metrics should I follow for that?

The ones you can easily collect in bulk.

I want to see the hosting / CDN speed only.

Far from clear what you mean here, but if you want to measure the overhead outside your origin server then you're going to have instrument each reverse proxy to uniquely tag each request and correlate that to the requests on the origin server. If that isn't obvious....?