What you are complaining about is the result of the guest mode and is caused by it. However, only for pages that are too “heavy”, i.e. have too many graphic elements. Normally you should only see a brief flickering of the page. The problem can only be solved to a limited extent with your “heavy site” by always keeping the cache warmuped, so that the site loads quickly through guest mode. There is no other way to do this, unless you disable guest mode.
you can try add
/ to Page Optm -> CSS tune -> UCSS exclude URI , purge all , see if it helps.
Even if you won’t like to hear that, you are essentially responsible for the problem yourself. Even in guest mode, the size of the CSS file is 1.3 MB. With 1.3 MB I format 10 websites, but actually I don’t even need 80kb. It’s not just about the size of the CSS file. Rendering CSS takes up the most resources in the browser and inevitably leads to delayed page loading. You basically have it in your own hands to make your site fast and performant, especially for mobile devices, because no plugin in this universe is able to reduce such a large amount of data. UCSS can solve the problem, but not in all cases as extensively as it would be necessary in your case.
OMG, It’s a normal ELEMENTOR site… Do you think I can reduce the CSS size or It’s Elementor fault?
This is probably not possible, since the problem with all the CSS is a typical problem of every Pagebuilder theme and also of the Bootstrap css framework.
Also, this type of themes produces 10x more HTML code, which makes the page even harder to render and therefore takes longer to load.