we had to set up the CDN again after problems with the SSL Certificates of our provider.
Before we booked APO, our website had a server time (measured in Matomo) of around 2,3 seconds. With APO of around 0,3 seconds.
After reinstalling the CDN at our provider, it went back to 2,3 seconds. The test as described in the tutorial looks ok.
But it looks like that the HTML is loading from our server, dynamically generated in Wordpress. And this takes 2 seconds longer, then getting the HTML directly from the CDN. So I assume that APO is somehow not configured correctly.
Now your installation has many dynamic elements which are not cacheable. For instance, requests to the Google Translator app, which is not part of your domain, and therefore is not proxied by Cloudflare, as well as requests to your domain with query strings, such as requests to the plugin Matomo.
Cloudflare APO only caches files in your domain, and when they do not have a query string or a cookie indicating the content is dynamic. If these requests were cached, your site would stop working as expected.
the dynamic elements had not been a problem before the reinstall. I think, Rocketloader should have deferred them to not cause this problem.
But I checked a few minutes ago and Rocketloader was not active in Cloudflare Dashboard after the reinstall. But it was loaded by the website.
I activated it and will see, if that will solve the problem.