Hello again!
Any post or page that’s been modified using a page builder will be detected. Pages that use the default WordPress Block or Classic editor will have their content taken as-is (with shortcodes and some various HTML blocks stripped), and that’s processed into a description. When you fill in a post/page excerpt, TSF will use that for generation, instead.
We have a filter guide, where we explain where you can add filters.
In any case, I think it’s best to fill in manual descriptions whenever you find the time to do so. Google can also generate descriptions for you, so bypassing the page builder check isn’t necessary.
As for the image, TSF automatically selects the first usable image from your page and sets that as an input placeholder. This starts with the featured image, followed by images from your content. If nothing is available, it’ll try fallbacks, like the one you set in the social settings, or from theme elements. Of course, you can overwrite this behavior when you hit the “Select Image” button, or when you manually fill in the image URL.
I hope this explains the lot ?? And thank you, @onestatero, for dropping by and sharing your knowledge!