In 2023, Page Builders that work outside the Gutenberg core are still a popular trend for designers and developers.
Gutenberg is a block editor introduced in WordPress 5.0 that allows users to create content using a block-based approach. It is a part of the core WordPress system and is designed to provide a simple and streamlined editing experience.
Page builders, on the other hand, are third-party plugins that provide more advanced functionality for designing and customizing websites. They typically offer a drag-and-drop interface and a range of pre-built elements and templates to help users create complex page layouts.
Oxygen and later Bricks Builder offer a professional workflow with a class-first approach. Both output semantically correct HTML compared to more popular builders like Divi and Elementor. That is because these legacy page builders nest divs multiple times and have a class on the div 3 levels up rather than on the Heading element itself, for example.