editor.js

wp.domReady(function () {
    yourTheme.updateLayoutClass();

    var layouts = document.querySelector(".genesis-layout-selector");
    if( null === layouts )
        return;
    layouts.addEventListener("input", function (e) {
        yourTheme.updateLayoutClass();
    });
});

var yourTheme = {
    getLayout: function () {
        var inputs = document.querySelectorAll(".genesis-layout-selector input");
        var layout = "";
        for (var i = 0, len = inputs.length; i < len; i++) {
            if (inputs[i].checked) {
                layout = inputs[i].getAttribute("id");
                break;
            }
        }
        if (layout === "default-layout") layout = yourThemeConfig.defaultLayout;
        return layout;
    },

    setWrapperClass: function (layout) {
        var root = document.querySelector("body");
        var classes = root.classList;
        classes.forEach(function(c){
            if (c.includes("genesis-")) root.classList.remove(c);
        });
        root.classList.add("genesis-" + layout);
    },

    updateLayoutClass: function() {
        var layout = yourTheme.getLayout();
        yourTheme.setWrapperClass(layout);
    }
};

functions.php

<?php

/**
 * Gutenberg scripts and styles
 *
 */
function ea_gutenberg_scripts() {
	wp_enqueue_style( 'ea-genesis-layout', get_stylesheet_directory_uri() . '/assets/css/genesis-layout.css' );
	wp_enqueue_script( 'ea-editor', get_stylesheet_directory_uri() . '/assets/js/editor.js', array( 'wp-blocks', 'wp-dom' ), filemtime( get_stylesheet_directory() . '/assets/js/editor.js' ), true );

	$post_id = isset( $_GET['post'] ) ? intval( $_GET['post'] ) : false;
	$post_type = isset( $_GET['post_type'] ) ? esc_attr( $_GET['post_type'] ) : false;
	$default_layout = ( !empty( $post_id ) && 'page' === get_post_type( $post_id ) ) || ( !empty( $post_type ) && 'page' === $post_type ) ? 'full-width-content' : genesis_get_default_layout();
	wp_localize_script( 'ea-editor', 'yourThemeConfig', array(
		'defaultLayout' => $default_layout,
	));
}
add_action( 'enqueue_block_editor_assets', 'ea_gutenberg_scripts' );

genesis-layout.css

.genesis-content-sidebar .editor-styles-wrapper .wp-block,
.genesis-sidebar-content .editor-styles-wrapper .wp-block {
	max-width: 640px;
}