I’m not a user of Mirage yet, so please take what I’ll say here with a grain of salt.
It seems that your test on Pingdom was done with a regular, desktop user agent. Mirage is supposed to work on mobile connections.
I ran your website on GTMetrix and webpagetest.org using mobile profiles, and in both cases the number of images being downloaded is very high. Most of the images come from ads, an inordinate number of them, many more than when the test is done using a desktop profile. You may want to check your settings on Google Ads (or any other ad platform you may use).
When I visited your website using Chrome with Developer Tools opened, I saw on the “initiator” column of the Network tab that all images coming from your domain are being initiated by Autoptimize. My guess is that Autoptimize is already lazy loading the images, and while doing it it may prevent Mirage from working properly. I’d suggest you try to deactivate Autoptimize, flush your caches, and do this test again. If that works, then you may want to test different settings in Autoptimize to try and make the best use of both this plugin and Mirage.
Having said that, despite the large number of HTTP requests, your site loads very fast in Brazil. I’ve navigated to a few pages using my cell phone on a 4G connection, and it does feel very fast, with all images and content properly displayed. Sometimes the testing tools give us a bleak report, because they don’t reflect the actual “looking at the screen” experience the users have. I for instance have a website with Rocket Loader on that has worse GTMetrix reports than when RL is off, even though RL took about a second off the load time!