Hi,

1. Try to replace the code in the functions.php file in the child theme

function woodmart_child_enqueue_styles() {
	$version = woodmart_get_theme_info( 'Version' );
	
	if( woodmart_get_opt( 'minified_css' ) ) {
		wp_enqueue_style( 'woodmart-style', get_template_directory_uri() . '/style.min.css', array('bootstrap'), $version );
	} else {
		wp_enqueue_style( 'woodmart-style', get_template_directory_uri() . '/style.css', array('bootstrap'), $version );
	}

    wp_enqueue_style( 'child-style', get_stylesheet_directory_uri() . '/style.css', array('bootstrap'), $version );
}

with this one

function woodmart_child_enqueue_styles() {
    wp_enqueue_style( 'child-style', get_stylesheet_directory_uri() . '/style.css', array( 'woodmart-style' ), woodmart_get_theme_info( 'Version' ) );
}

2. Mega menu dropdowns built with HTML Blocks are supported by the main desktop menu only. You need to create a separate mobile navigation in Appearance -> Menus without HTML Blocks dropdowns.

Regards