It looks like the page does not load until your mouse moves or performs some other interaction. As Lighthouse doesn’t do any interactions it just sees a white page and so fails.
While it can be good to lazy load non-critical content not loading ANY content is a very poor use of that pattern.
Something I see a lot with some plugins is that this sort of thing is often done to cheat Lighthouse to make it look like it’s more performant than it really is, and so make the plugin look like it’s doing a lot for you even when it is not helping your real users. Check your WordPress plugins to see which one doing this.
Now it could be the plugin is intending to be helpful and holding back JavaScript under the assumption that your page can render without JavaScript and that the JavaScript is not needed until after initial page load, but clearly that assumption is wrong. And in my experience these types of optimization plugins are doing it for Lighthouse cheating reasons rather than for good usability reasons. Which is why the plugins that do this annoy me no end.