Resolved my own issue. Posting here in case other experience issue.
Jevelin and Unyson are not compatible with AMP plugin. It was rendering mobile views in other ways. Removed that plugin and all is good.
Part 2: Then we used CSS to remove the menu from template in all modes.
we put the code in the header.php. we were using the a jevelin theme, but the idea will be the same with other themes:
Jevelin: Theme Header (header.php)
<header class=”primary-desktop<?php echo jevelin_header_desktop_style(); ?>”>
<?php /* Inlcude desktop header */
get_template_part(‘inc/headers/header-‘.jevelin_header_layout() );
?>
</header>
<?php endif; ?>
/* PUT THE CODE IN THE NEXT LINE */
<?php wp_nav_menu( array( ‘theme_location’ => ‘header’ ) ); ?>
/* ————————————————————————-*/
<?php
/* Inlcude breadcrumbs HTML, if not bottom titlebar style */
if( $titlebar_style_val2 != ‘bottom_titlebar’ ) :
get_template_part(‘inc/templates/titlebar’ );
endif;