If you’re looking for something super simple—without needing Elementor or WPBakery—you might want to look at CMP Coming Soon & Maintenance Mode. It isn’t an AI page builder, but it does let you spin up a clean landing page and adding photo and text on the site
You don’t need to manually change every Gutenberg gallery. Smush Pro plugin can handle this for you without editing a single post.
Smush Pro’s Serve Scaled Images feature automatically delivers the correctly sized version of each image based on how it appears on the page—even if the gallery is set to “Large.” Combined with Bulk Smush compression and optional WebP conversion or the Smush CDN (which can dynamically resize images), your pages will load much faster with no manual work.
In short: keep your galleries as they are, and let Smush Pro optimize and serve the right sizes automatically.